Cook elbow macaroni to al dente in well salted water according to package instructions. Drain and set aside.
In a large skillet, heat butter over medium-high until melted. Sprinkle in the all-purpose flour to form a paste. Cook for 2 minutes, stirring frequently with a silicon whisk, until flour is lightly browned.
Slowly whisk in the milk, stirring constantly. Sprinkle in the salt, pepper and old bay seasoning. Add in the shredded cheddar and gouda. Stir until cheese is completely melted.
Bring to a simmer over medium-high heat. Once the sauce is bubbling, reduce heat down to low. Let simmer over low heat until thickened. The sauce is ready when it’s thick enough to coat the back of a spoon without sliding off.
Add the cooked macaroni to the sauce and stir to combine. Serve topped with paprika and additional black pepper.
Storage: Keep refrigerated in a closed container for 3-4 days.Reheating: To reheat, add a splash of milk and heat in the microwave for 1-2 minutes, until warmed through. Reheat on the stovetop with a splash of milk over low heat.Substitutions: Gouda can be replaced with mild cheddar or gruyere.