extra-virgin olive oil
sweet italian sausage, remove from casing
cloves garlic, minced
crushed red pepper flakes
(28-oz.) can whole peeled tomatoes, pulsed in a blender
sprig of fresh basil, plus more chopped for garnish
Kosher salt
Freshly ground black pepper
Penne pasta
large egg
ricotta
freshly grated Parmesan, divided
shredded mozzarella, divided