01 - Position rack in center and preheat oven to 375°F.
02 - Grease an 8x8-inch baking dish lightly with olive oil.
03 - Heat olive oil in a skillet over medium heat. Sauté spinach until wilted, about 2 minutes. Remove from heat.
04 - Whisk eggs and milk together in a large bowl until well blended. Season with salt and pepper.
05 - Fold wilted spinach, bread cubes, and crumbled feta into the egg mixture until evenly incorporated.
06 - Pour mixture into the prepared baking dish, spreading evenly.
07 - Bake uncovered for 30-35 minutes, or until center is just set and top is golden brown.
08 - Allow to cool for 5 minutes before slicing and serving.