For Mac and Cheese: 

In a medium sauce pan, boil the medium shells for 8-10 minutes until al dente.

While the noodles are cooking let the 2 cups of milk come to a simmer in a medium sauce pan. Whisk the remaining 1/2 cup of milk and 1/4 cup of flour together in a bowl until the flour is combined. Add to the cups of milk that is simmering on the stove top. Let the milk and flour thicken for another 5 minutes. Add in salt and pepper for seasoning.

Stir in the cheese until melted and combine the cheese with the noodles.

For Pizza: 

Preheat oven to 400 degrees. 

Spread 1 to 2 cups of prepared Mac and cheese on top of pizza crust. Then sprinkle the cheese over the top. Bake in an oven for 10 to 15 minutes. 

Take the pizza out and garnish the pizza with diced bacon.