01 - Preheat oven to 350°F (180°C). Grease a 12-cup muffin tin lightly or insert silicone liners.
02 - In a skillet over medium heat, crumble turkey sausage and cook until browned and fully cooked. Drain any excess fat.
03 - Add diced red bell pepper and chopped spinach to the skillet. Cook for 2 to 3 minutes until the vegetables are just softened. Remove from heat and allow to cool slightly.
04 - In a large bowl, whisk together eggs, milk, garlic powder, paprika, salt, and pepper until smooth.
05 - Stir the cooked sausage, sautéed vegetables, sliced green onions, and shredded cheddar cheese (if using) into the egg mixture.
06 - Evenly spoon the mixture into the prepared muffin cups, filling each about three-quarters full.
07 - Transfer the tin to the oven and bake for 20 to 25 minutes, or until eggs are set and tops are lightly golden.
08 - Allow muffins to cool in the tin for 5 minutes before removing. Serve warm or let cool fully before storing.