Cook macaroni according to package directions. Drain, set aside.
In a saucepan over medium heat, melt butter. Add flour and stir to combine, creating a paste. Cook for 1 minute. Add milk, salt, pepper, paprika, and ground mustard, and whisk constantly to combine. Cook for 1-2 minutes, or until mixture thickens slightly.
Reduce heat to low. Add shredded cheeses and stir until cheese is melted and fully incorporated.
Add drained macaroni and stir to combine. Remove from heat and serve immediately.
Recipe can be made with all shredded cheddar, or all gruyere cheese if preferred.
Cheese sauce too thick? Add a splash of milk.
Recipe can be made with macaroni, shells, or your favorite medium sized pasta.