Step 1

Preheat the oven to 375°F (190°C).

Step 2

Cook pasta shells in salted water until al dente. Drain and set aside to cool slightly.

Step 3

In a skillet over medium heat, brown the ground beef. Add minced garlic and oregano, cooking until fragrant. Remove from heat.

Step 4

In a bowl, mix the cooled beef with ricotta, 1 cup mozzarella, Pecorino Romano, beaten egg, salt, and pepper.

Step 5

Spread 1 cup of tomato basil sauce on the bottom of a baking dish.

Step 6

Fill each pasta shell with the beef and cheese mixture, placing them snugly in the dish.

Step 7

Pour the remaining sauce over the shells and sprinkle the remaining ½ cup of mozzarella on top.

Step 8

Cover with foil and bake for 25 minutes. Remove the foil and bake for an additional 10 minutes, or until cheese is golden and bubbly.

Step 9

Let it cool slightly, garnish with chopped parsley, and serve warm.