Preheat the oven to 350°F. Spray a 9×11 casserole dish with nonstick cooking spray. Set aside.
Heat a frying pan over medium high heat. Add the 6 bacon slices (chopped small) and cook until the pieces are crispy. Once cooked, transfer the crispy bacon to a plate with paper towel and set aside. Soak up the excess grease by swishing a folded paper towel around the pan with a spatula, leaving 2 tsp worth of grease in the frying pan.
Now add 1 cup chopped yellow onion, 1 cup chopped green bell pepper, and 1 cup chopped red bell pepper to the frying pan. Mix together and cook until the vegetables soften, about 3-4 minutes.
Mix in ⅓ cup chopped green onions and stir together. Cook for 1 minute, until the green onion softens. Now turn off the heat and remove the pan. Set it aside for now.
In a large bowl, add 12 large eggs along with ½ tsp dried basil, ½ tsp garlic powder, and ¼ tsp ground black pepper. Beat the eggs together with an electric hand mixer or a whisk.
Pour the cooked onions and bell peppers into the egg mixture, along with the cooked bacon pieces and 1 cup shredded cheddar cheese. Mix everything together.
Pour the mixture into the greased casserole dish and bake for 35-45 minutes, until the center is no longer liquid, the edges are golden brown and a toothpick comes out clean when poked in the center. Let cool for 10 minutes before slicing to serve.