Step 1

Cook pasta per package directions; drain and rinse.

Step 2

Heat oven to 400°F. Coat 24-cup mini muffin pan with nonstick cooking spray.

Step 3

In medium bowl, whisk together egg whites and 1/4 teaspoon salt. Toss with cooked spaghetti to coat, then fold in Parmesan and mozzarella. Place 1 heaping tablespoon pasta mixture in each cup of muffin pan. Press pasta down in center and up sides to create nest. Bake until golden brown, 12 to 15 minutes. Transfer nests to platter.

Step 4

Heat meatballs per package directions, then toss in marinara sauce. Top each nest with 1 meatball and sprinkle with grated Parmesan, if desired.