Copycat Panera Macaroni and Cheese

1/4 cup unsalted butter
1/4 cup all-purpose flour
1 cup milk
2 cup heavy cream
2 cup shredded white cheddar
1/2 tsp kosher salt
1/2 tsp black pepper
1 tsp dry mustard
1lb, pasta, cooked (cavatapppi, shells, or elbow)

Cook pasta according to package directions while making the sauce. Drain and set aside until ready to use.  In a large pot on medium high heat, add butter until melted. Whisk in the flour and cook for about one minute. Reduce heat to medium and add milk, heavy cream, salt, dry mustard and pepper. Continue whisking until it begins to bubble. Reduce to low and add white cheddar. Stir until melted. Add cooked pasta, stirring until combined. Remove from heat and allow to sit about 5 minutes to thicken. Season with additional salt and pepper if desired. ENJOY.