Preheat oven to 375 F.
Brown sausage in a frying pan and break up into very small chunks. Drain well and press out excess fat using paper towels. Transfer drained sausage to the bottom of a lightly greased 9x13 baking dish and spread evenly.
Place baby spinach on top of the sausage.
Sautee diced peppers and onions until the onions become translucent. Don't overcook!
Scoop cooked veggies evenly over the spinach.
In a large mixing bowl, whisk together 8 eggs until well scrambled. Add in egg whites, salt, black pepper, and garlic powder and whisk until blended in.
Pour the egg mixture evenly over the casserole.
Sprinkle the top of the casserole evenly with shredded pepper jack cheese. You can use more if you'd like, but that will increase the fat content per serving.
Bake for 30-35 minutes, until the eggs are set.
Allow the casserole to cool for 5 minutes before cutting and serving.
Store any leftovers in an airtight container in the refrigerator for up to 1 week.
