Leftover Mashed Potato Pizza

Name: Leftover Mashed Potato Pizza
Ingredients: 5 ounces slab bacon, finely diced (about 1 cup); 1 1/2 pounds prepared pizza dough, at room temperature; All-purpose flour; Olive oil, for drizzling; Kosher salt and freshly ground black pepper; 3 cups leftover mashed potatoes, slightly warm; 1 1/2 cups shredded mozzarella (about 5 ounces); 1/2 leek (white and light green parts only), very thinly sliced; 1 clove garlic, minced; 1/2 cup freshly grated Parmesan or Pecorino Romano cheese (about 1 ounce); 12 fresh basil leaves; Crushed red pepper flakes, optional