Melt butter in a medium saucepan over medium-low heat. Add flour and whisk until blended and a paste forms, about 1 minute.
Whisk in mustard until blended. Slowly whisk in half of the milk and all of the heavy cream until well blended. Whisk in remaining milk and bring to a boil over medium-high heat.
Stir in 2 packages Knorr® Cheesy Cheddar Pasta Side and return to a boil. Reduce heat and continue cooking for 10 minutes or until pasta is tender.
Remove from heat and stir in garlic powder, black pepper and 1/2 cup cheese. Transfer to a 9-inch square baking dish.
Toss remaining 1/2 cup cheese with paprika. Sprinkle evenly over the pasta.
Bake for 7 to 10 minutes or until the cheese is melted and well browned.
