Heat oven to 350°F; grease a 9x13-inch dish.
Cook macaroni to package directions until al dente; drain and set aside.
Melt butter in a large saucepan over medium heat; whisk in flour and cook 1-2 minutes until golden.
Gradually whisk in milk; stir constantly until thickened and gently simmering, about 5-7 minutes.
Remove from heat; stir in cheddar and Colby until completely melted and smooth.
Add salt, pepper, and paprika; fold in macaroni to coat evenly.
Pour into prepared dish; bake 20-25 minutes until bubbly and golden.
Let stand 5 minutes before serving.