Preheat the oven to 350°F/180°C/Gas 4. Spray a 9 x 13-inch (23 x 33 cm) baking dish with cooking spray or lightly grease with olive oil.
Heat the olive oil in a large skillet over medium heat. Add the onion, green bell pepper, red bell pepper, and mushrooms. Season with salt and black pepper and cook for 8-10 minutes, stirring occasionally, until softened and lightly browned.
Stir the frozen peas into the vegetables, then remove the skillet from the heat.
Place the eggs, milk, and cottage cheese in a large mixing bowl and whisk until combined. Stir in the crumbled goat cheese and season with salt and black pepper to taste.
Add the cooked vegetable mixture to the egg mixture and stir until evenly combined.
Pour the mixture into the prepared baking dish and sprinkle the shredded mozzarella evenly over the top.
Bake for 35-40 minutes, until the edges are golden brown and the center is set.
Allow the breakfast casserole to cool for 10 minutes before slicing. Serve and enjoy!
Notes
Tips
Cook the mushrooms and peppers until softened and lightly browned before adding them to the casserole for the best flavor and texture.
There's no need to thaw the frozen peas before adding them to the skillet.
The casserole is ready when the center is set and no longer appears wet or jiggly.
Allow the casserole to rest for 10 minutes after baking to make it easier to slice and serve.
Substitutions
You can use sour cream instead of cottage cheese.
Leftovers
Let leftovers cool before transferring them to an airtight container and refrigerating.
Reheat individual portions in the microwave or warm them in the oven until piping hot throughout.
Freezing
Allow the cooked casserole to cool completely before freezing.
Cut into individual portions and place in freezer-safe airtight containers for convenient reheating.
Thaw overnight in the refrigerator, then reheat thoroughly until piping hot throughout.