Kerang Isi Keju Pesto

Bahan-bahan (6 porsi)

• 2 tablespoons extra virgin olive oil
• 1 pound ground spicy Italian sausage
• 2 (28 ounce) cans san marzano tomatoes
• 1/2 cup vodka
• 2 teaspoons dried oregano
• 1 pinch crushed red pepper flakes
• kosher salt and pepper
• 1 pound jumbo shells
• 16 ounces whole milk ricotta cheese (about 2 cups)
• 2 cups shredded provolone or fontina cheese
• 3/4 cup basil pesto, homemade or store bought
• 8 ounces mozzarella, torn
• fresh basil for serving