Chunky Monkey Oatmeal Cookie Skillet

Featured in: Desserts

This warm, shareable oatmeal cookie skillet brings together the beloved flavors of banana, chocolate, and walnuts in one delicious dessert. Baked in a cast-iron pan until golden at the edges with a soft, chewy center, it combines old-fashioned oats, mashed ripe bananas, semisweet chocolate chips, and chopped walnuts. Ready in just 40 minutes, this easy vegetarian dessert serves 8 and pairs perfectly with vanilla ice cream for an indulgent treat.

Updated on Sat, 31 Jan 2026 12:45:00 GMT
Golden-baked Chunky Monkey Oatmeal Cookie Skillet fresh from the oven, featuring melted chocolate chips and chopped walnuts. Save
Golden-baked Chunky Monkey Oatmeal Cookie Skillet fresh from the oven, featuring melted chocolate chips and chopped walnuts. | cheerfulchefs.com

My sister brought her cast-iron skillet over one rainy Saturday and announced we were making dessert in it. I thought she was joking until she started mashing bananas into cookie dough with the confidence of someone who'd done this a hundred times. The smell of warm oats, melting chocolate, and toasted walnuts filled the kitchen within twenty minutes. We ate it straight from the pan with two spoons, and I haven't made cookies any other way since.

I made this for a friend's birthday once, and she kept asking what made it taste so familiar. When I told her it was banana, chocolate, and walnuts, she laughed and said it was like eating her breakfast smoothie as dessert. We served it with vanilla ice cream that melted into every warm crevice, and she declared it her new favorite thing. Now she requests it every year instead of cake.

Ingredients

  • Old-fashioned rolled oats: They give the cookie a hearty chew and soak up the banana moisture beautifully, so don't swap them for quick oats or the texture will fall flat.
  • All-purpose flour: This holds everything together without making it cakey, just enough structure to slice cleanly once it cools a bit.
  • Baking soda and baking powder: The duo creates a gentle rise and soft crumb, and skipping either one will leave you with a dense puck instead of a tender cookie.
  • Unsalted butter, melted: Melted butter blends into the sugars easily and keeps the dough spreadable, plus it adds that rich, toasty flavor you expect from a skillet dessert.
  • Light brown sugar and granulated sugar: Brown sugar brings molasses depth and chewiness, while granulated sugar crisps the edges, and together they balance perfectly.
  • Egg: One large egg binds everything and adds moisture, so make sure it's at room temperature for smoother mixing.
  • Pure vanilla extract: A teaspoon brightens the whole batter and makes the chocolate and banana sing, so use the real stuff if you can.
  • Ripe bananas, mashed: They should be spotted and soft, almost too ripe to eat plain, because that's when they're sweetest and blend into the dough without chunks.
  • Semisweet chocolate chips: They melt into gooey pockets throughout the skillet, and semisweet keeps it from being too sugary.
  • Chopped walnuts: Toasted walnuts add crunch and a slight bitterness that balances all the sweetness, and chopping them yourself ensures even distribution.
  • Chopped dark chocolate (optional): If you want extra richness and deeper chocolate flavor, toss in some chopped dark chocolate for pockets of intense melty goodness.

Instructions

Product image
Dries dishes, utensils, and cookware neatly after cooking, keeping your countertop organized and clutter free.
Check price on Amazon
Prep the skillet:
Preheat your oven to 350°F and grease a 10-inch cast-iron skillet generously with butter or nonstick spray. A well-greased pan means you can scoop out warm slices without them sticking to the bottom.
Mix the dry ingredients:
Whisk together the oats, flour, baking soda, baking powder, and salt in a medium bowl until evenly combined. This step prevents clumps and makes sure every bite has the right texture.
Cream the wet base:
In a large bowl, stir together the melted butter, brown sugar, and granulated sugar until smooth and glossy. It should look like wet sand turning into caramel.
Add egg, vanilla, and banana:
Beat in the egg and vanilla, then fold in the mashed bananas until the mixture is pale and creamy. The banana will lighten the color and add natural sweetness.
Combine wet and dry:
Gently fold the dry ingredients into the wet mixture using a rubber spatula, stirring just until no flour streaks remain. Overmixing will make the cookie tough, so stop as soon as it comes together.
Fold in the chunky add-ins:
Stir in the chocolate chips, walnuts, and dark chocolate if using, making sure they're evenly distributed. You want every scoop to have a little bit of everything.
Spread into the skillet:
Pour the batter into your prepared skillet and spread it out evenly with the spatula, pushing it gently to the edges. The dough will be thick and sticky, which is exactly right.
Bake until golden:
Bake for 22 to 25 minutes, until the edges are set and golden and the center still looks slightly soft. A toothpick inserted in the middle should come out with a few moist crumbs clinging to it.
Cool and serve:
Let the skillet cool for 10 minutes on a wire rack before serving warm. It's perfect with a scoop of vanilla ice cream melting into the center.
Product image
Dries dishes, utensils, and cookware neatly after cooking, keeping your countertop organized and clutter free.
Check price on Amazon
Warm Chunky Monkey Oatmeal Cookie Skillet served with melting vanilla ice cream on top for a decadent dessert. Save
Warm Chunky Monkey Oatmeal Cookie Skillet served with melting vanilla ice cream on top for a decadent dessert. | cheerfulchefs.com

There was a night when I pulled this out of the oven just as friends showed up unannounced, and we sat around the kitchen counter with forks and spoons, laughing and fighting over the corner pieces. Someone said it tasted like childhood and comfort all at once, and I realized that's exactly what a warm skillet dessert is supposed to feel like. It's not fancy, but it turns any ordinary moment into something you want to remember.

How to Store and Reheat Leftovers

Cover the skillet tightly with foil or transfer slices to an airtight container, and they'll keep in the fridge for up to four days. When you're ready to eat, warm individual slices in the microwave for about 20 seconds, or reheat the whole skillet in a 300°F oven for 10 minutes until it's gooey again. The texture is best when it's warm, so don't skip the reheating step if you want that fresh-baked feel.

Swaps and Substitutions

If you want to make this vegan, swap the butter for melted coconut oil and replace the egg with a flax egg made from one tablespoon of ground flaxseed mixed with two and a half tablespoons of water. Pecans work just as well as walnuts if that's what you have on hand, and you can toss in dried cherries or shredded coconut for a tropical twist. I've also made this with gluten-free all-purpose flour, and it turned out just as chewy and delicious, though it was slightly more crumbly around the edges.

Serving Suggestions

This skillet is incredible with a big scoop of vanilla ice cream melting into the warm center, but it's also great with whipped cream, a drizzle of caramel sauce, or even a dollop of peanut butter. I've served it for brunch with coffee, as a dessert after dinner, and once as a late-night snack straight from the fridge with cold milk.

  • Top with sliced bananas and a sprinkle of cinnamon for extra banana flavor.
  • Drizzle with melted peanut butter or Nutella for a richer finish.
  • Serve with a side of fresh berries to cut through the sweetness.
Product image
Deep clean greasy stovetops, countertops, sinks, and tiles using powerful steam after everyday cooking.
Check price on Amazon
A close-up of a gooey slice of Chunky Monkey Oatmeal Cookie Skillet highlighting ripe banana chunks and rich chocolate. Save
A close-up of a gooey slice of Chunky Monkey Oatmeal Cookie Skillet highlighting ripe banana chunks and rich chocolate. | cheerfulchefs.com

This skillet has become my go-to when I want something warm and comforting without spending an hour in the kitchen. It's forgiving, delicious, and always makes people smile when you set it down in the middle of the table with a pile of spoons.

Recipe FAQs

Can I make this without a cast-iron skillet?

Yes, you can use any 10-inch oven-safe pan or baking dish. Adjust baking time as needed based on your pan's material and depth.

How ripe should the bananas be?

Use ripe bananas with brown spots for the best flavor and natural sweetness. They should mash easily and provide moisture to the batter.

Can I substitute the walnuts with other nuts?

Absolutely! Pecans work wonderfully as a direct substitute, or try almonds or hazelnuts for a different flavor profile.

How do I store leftovers?

Cover the skillet tightly with plastic wrap or transfer to an airtight container. Refrigerate for up to 3 days. Reheat individual portions in the microwave for 15-20 seconds.

Can this be made vegan?

Yes, replace the butter with coconut oil and use a flax egg (1 tablespoon ground flaxseed mixed with 2.5 tablespoons water). Ensure your chocolate chips are dairy-free.

Why is the center still soft after baking?

This is intentional for a gooey, cookie-like texture. The skillet continues cooking slightly after removal from the oven. A few moist crumbs on a toothpick indicate perfect doneness.

Chunky Monkey Oatmeal Cookie Skillet

Golden oatmeal cookie skillet with banana, chocolate chips, and walnuts baked in cast iron for shareable dessert.

Prep Time
15 minutes
Cook Time
25 minutes
Overall Time
40 minutes
Creator Ruby Smiles

Recipe Type Desserts

Skill Level Easy

Cuisine Background American

Portions 8 Serves

Dietary Preferences Vegetarian-Friendly

What You’ll Need

Dry Ingredients

01 1½ cups old-fashioned rolled oats
02 1 cup all-purpose flour
03 ½ teaspoon baking soda
04 ½ teaspoon baking powder
05 ¼ teaspoon salt

Wet Ingredients

01 ½ cup unsalted butter, melted
02 ⅓ cup light brown sugar, packed
03 ⅓ cup granulated sugar
04 1 large egg
05 1 teaspoon pure vanilla extract

Chunky Monkey Add-ins

01 2 ripe bananas, mashed (approximately 1 cup)
02 ½ cup semisweet chocolate chips
03 ½ cup chopped walnuts
04 ½ cup chopped dark chocolate, optional

Step-by-Step Guide

Step 01

Prepare Skillet and Preheat Oven: Preheat oven to 350°F. Grease a 10-inch cast-iron skillet with butter or nonstick spray.

Step 02

Combine Dry Ingredients: In a medium bowl, whisk together oats, flour, baking soda, baking powder, and salt. Set aside.

Step 03

Mix Wet Base: In a large bowl, combine melted butter, brown sugar, and granulated sugar. Mix until well combined and creamy.

Step 04

Incorporate Egg and Banana: Beat in egg and vanilla extract, then stir in mashed bananas until fully incorporated.

Step 05

Fold Dry and Wet Ingredients: Gradually fold dry ingredients into wet mixture until just combined. Do not overmix.

Step 06

Add Mix-ins: Gently fold in chocolate chips, walnuts, and chopped dark chocolate if using.

Step 07

Transfer to Skillet: Spread batter evenly into prepared skillet.

Step 08

Bake: Bake for 22 to 25 minutes, until edges are golden and a toothpick inserted in center comes out mostly clean with a few moist crumbs acceptable.

Step 09

Cool and Serve: Cool for 10 minutes before serving. Serve warm directly from skillet, optionally topped with vanilla ice cream.

Tools You’ll Need

  • 10-inch cast-iron skillet or oven-safe baking pan
  • Medium and large mixing bowls
  • Whisk
  • Rubber spatula
  • Measuring cups and spoons

Potential Allergens

Inspect ingredients for specific allergens and contact a professional for concerns.
  • Contains wheat and gluten
  • Contains eggs
  • Contains milk products from butter and chocolate chips
  • Contains tree nuts—walnuts

Nutritional Details (Per Serving)

Provided as supportive info; always cross-check with your healthcare provider.
  • Calories: 310
  • Fats: 15 grams
  • Carbohydrates: 41 grams
  • Proteins: 5 grams