Step 1

In a large microwavable bowl, heat milk in microwave until warm. Cover and set aside.

Step 2

Fill up a large pot with salted water. Bring to a boil.

Step 3

Meanwhile, in a medium saucepan, melt butter and add flour. Whisk briskly and constantly for about 4 minutes or until the roux is golden yellow and completely smooth (no longer grainy at all.) Add warm milk and whisk until thick and bubbly. Add salt, mustard, cayenne, black pepper, and cheeses. Stir until cheeses are melted and sauce is smooth and creamy. Cover and set aside to keep warm.

Step 4

Add uncooked macaroni noodles to the large pot of boiling water. Cook until al dente, according to package instructions. Drain cooked macaroni in a colander and transfer drained noodles back into the empty large pot.

Step 5

Using a rubber spatula, transfer cheese sauce into the pot with cooked/drained macaroni and stir until well coated.

Step 6

Serve immediately with cooked/crumbled bacon.