01 - Preheat oven to 350°F (175°C). Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together whole wheat flour, rolled oats, vanilla whey protein powder, coconut sugar or light brown sugar, baking powder, baking soda, and salt.
03 - In a separate bowl, whisk together eggs, unsweetened applesauce, Greek yogurt, milk, and vanilla extract until fully incorporated.
04 - Add wet ingredients to dry mixture and stir gently until just combined. Avoid overmixing.
05 - Carefully fold mixed berries into the batter.
06 - Scoop 1/4 cup portions of batter onto prepared baking sheet, spacing each mound about 2 inches apart.
07 - Bake for 13 to 15 minutes, or until golden and a toothpick inserted into the center comes out clean.
08 - Allow muffin tops to cool on baking sheet for 5 minutes, then transfer to a wire rack to cool completely.