Heat the oven to 350°F. Lightly grease a 9×13-inch baking dish, then set it aside.
Place the diced bacon in a large skillet over medium heat and cook until it begins to soften.
Add the minced garlic and finely chopped onion. Continue cooking until the bacon starts to brown.
Stir in the diced red and green bell peppers. Cover the skillet and cook for 5–10 minutes, stirring occasionally, until the peppers are tender and the bacon is browned. Remove the skillet from the heat and allow the mixture to cool.
Crack the eggs into a medium mixing bowl and whisk until evenly blended.
Add the sea salt and black pepper, then whisk again until the seasonings are thoroughly incorporated.
After the bacon and vegetable mixture has cooled, stir it into the beaten eggs until evenly distributed.
Fold the shredded cheddar into the egg, bacon, and vegetable mixture, mixing until the cheese is dispersed throughout.
Transfer the mixture to the prepared 9×13-inch baking dish and spread it into an even layer.
Place the casserole in the preheated oven and bake for 25–30 minutes, or until the top is set and lightly browned.
Remove the baking dish from the oven and allow the casserole to rest for 5 minutes before serving warm.