Preheat the oven to 350 degrees. Generously spray 18 muffin cups with nonstick cooking spray.In a large skillet over medium-high heat, crumble and cook the sausage until it’s about ¾ brown. Add the onion and reduce the heat to medium-low. Stir and continue cooking the sausage, stirring occasionally, until the sausage is cooked and the onion is soft. Remove this from the heat and set it aside to cool.Crack the eggs into a bowl and add the salt, pepper, and chili powder. Whisk it until it’s combined. Add the cheddar and bell pepper and stir them in. When the sausage has cooled slightly, Add it by the spoonful and stir it until it’s all mixed together.Use a measuring cup to scoop the mixture into the muffin cups and bake them for 20-22 minutes, until they’re puffy and just barely set. Within a minute or two, the casseroles will start to flatten just a little bit. This is normal! Run a knife along the edges of each muffin cup and lift them out of the pan. Serve them warm with a little fruit.Helpful tip: The casseroles freeze beautifully! Just seal them tightly in plastic zipper bags. Thaw and reheat in the microwave when you’re ready to serve them.Change it up!• Substitute half the diced bell pepper with finely chopped mushrooms.• Add several dashes of hot sauce to the egg mixture for a little more spice.• Substitute pepper jack cheese for the cheddar.