In a large bowl, whisk together eggs, sour cream, heavy cream, cheddar cheese, salt and pepper until combined.
Heat a large skillet over medium heat. Add sausage and cook until browned, breaking into small pieces with a wooden spoon as it cooks. Drain most of the grease and add sausage to the bowl with egg mixture.
Add the onion and peppers to the same skillet the sausage was cooked in. Saute 4-5 minutes util softened. Add to egg mixture in bowl and stir to combine.
Pour mixture into baking dish and bake for 45-50 minutes or unitl the edges are golden brown and set and the center is just barely jiggly. Check with a toothpick, if it comes out clean in center, it is done.