Whisk together the eggs, egg whites, milk, salt, and Tabasco sauce. Set aside.

In a 9" oven-safe skillet (a cast iron skillet is perfect), cook the sausage. Remove from pan and drain on a paper towel.

Return the pan to heat and heat the olive oil over medium heat. Add the kale, green onions, and garlic and cook, stirring frequently, until the kale is wilted. Add the pepper or tomatoes and cook for a few additional minutes, until the pepper starts to become tender or the tomatoes are ready to burst.

Turn the oven broiler to high.

Sprinkle the cooked sausage evenly over the veggies. Sprinkle the feta over the sausage, then carefully pour the egg mixture evenly over everything else. Cook for 5-6 minutes over medium heat, completely leaving the pan alone. Place the pan in the heated oven for 2-3 minutes or until the frittata is setting up and starting to just turn brown in a few spots on top (with the broiler, you'll go from almost done to burned in just a few seconds, so don't go anywhere.) You may need to turn the pan if some spots are getting too done while others aren't quite done enough. When done, remove the pan from the oven and allow to stand for 5-10 minutes before cutting. Serves 4-6.