Preheat oven to 400 degrees Fahrenheit. On a large parchment-lined baking sheet, lay down 6 even dollops of red sauce spaced at least 2 inches apart.

Add one quartered meatball on top of each sauce dollop, then sprinkle with Parmesan cheese and place divided mozzarella on top of each.

Cut puff pastry sheets into 6 rectangles about 2 inches wide and 4 inches long. Lay each piece of puff pastry over each meatball, sauce, and cheese portion, gently pressing down the borders of the pastry to seal in the ingredients.

Whisk the egg thoroughly in a small bowl, then use a pastry brush to brush a thin layer of egg wash on top of each piece of pastry.

Place in oven to bake for about 15 minutes, or until the pastry is golden brown.

Use a spatula to flip the pastries to reveal the meatballs, sauce, and cheese, then garnish with fresh basil.