01 - Preheat oven to 350°F. Grease a 12-cup muffin tin or line with paper liners.
02 - Boil elbow macaroni according to package instructions just until al dente. Drain and set aside.
03 - In a small saucepan, melt butter over medium heat. Whisk in flour and cook for 1 minute. Gradually add milk, whisking constantly. Cook until slightly thickened, about 2–3 minutes.
04 - Remove saucepan from heat. Stir in cheddar cheese, salt, and pepper until cheese melts and sauce is smooth. Fold in the cooked macaroni and mix well. Allow the mixture to cool slightly.
05 - In a large bowl, vigorously whisk eggs, milk, salt, pepper, and paprika until fully blended.
06 - Add the macaroni and cheese mixture to the eggs. Fold in ham or bacon if using, as well as chives and spinach. Mix gently to combine.
07 - Evenly divide the mixture among the prepared muffin cups.
08 - Bake for 20 to 25 minutes until muffins are puffed, golden, and a toothpick inserted in the center comes out clean.
09 - Cool muffins in the pan for 5 minutes, then transfer to a wire rack. Serve warm.