01 - Preheat oven to 350°F and lightly grease a 12-cup muffin tin or line with silicone liners.
02 - In a skillet over medium heat, cook turkey sausage, breaking it up with a spatula, until evenly browned and fully cooked. Drain any excess fat.
03 - Add diced red bell pepper and chopped spinach to the skillet. Sauté for 2–3 minutes until vegetables are softened. Remove from heat and let cool slightly.
04 - In a large mixing bowl, whisk together eggs, milk, garlic powder, paprika, salt, and pepper until well combined.
05 - Add the cooled sausage and vegetable mixture, sliced green onions, and shredded cheese (if using) to the eggs. Stir gently to incorporate.
06 - Divide the mixture evenly among the 12 muffin cups, filling each about three-quarters full.
07 - Bake for 20–25 minutes, or until the muffins are set and tops are lightly golden.
08 - Allow muffins to cool for 5 minutes before removing from the tin. Serve warm or cool completely for storage.