Macaroni and Cheese Pizza with Bacon and Green Onions

pizza dough for one pizza crust

elbow macaroni

unsalted butter

large eggs

evaporated milk

cayenne

mustard powder

salt and pepper

sharp white cheddar, grated and divided

center-cut bacon, cut into thin strips, cooked until crisp, grease drained

green onions, sliced, for topping/garnish