Preheat your oven to 175°C (350°F). Grease a 9x13 inch baking dish with butter or non-stick spray to prevent sticking. Gather all your ingredients nearby for easy assembly.
In a large mixing bowl, crack in the eggs and whisk until they’re well combined and slightly frothy—this helps create a light, fluffy texture. Season with a pinch of salt and pepper.
Chop or crumble your cooked bacon or sausage, then add it to the eggs along with shredded cheese, chopped bell peppers, and spinach. Gently fold everything together until evenly distributed.
Pour the mixture into your prepared baking dish, spreading it out evenly with your spatula. Gently press down to help everything settle into an even layer.
Place the dish in the oven on the middle rack. Bake for about 35-40 minutes, until the top is golden brown and bubbling, and the center is just set but still slightly jiggly when shaken.
Check for doneness by inserting a toothpick into the center; it should come out clean. If needed, bake for an additional 5 minutes until fully cooked.
Remove the casserole from the oven and let it rest for 5-10 minutes. This allows it to set and makes slicing easier. Sprinkle with chopped herbs for a fresh finish.
Slice into squares and serve warm. The dish should be tender, golden, and fragrant, with a cheesy, hearty aroma filling the kitchen.
