French Onion Stuffed Shells Recipe
Prep Time:
20 minutes
Cook Time:
1 hour, 15 minutes
Servings:
5 Servings
Ingredients
  • 2 tablespoons unsalted butter
  • 4 sweet onions, thinly sliced
  • 1 ½ teaspoons salt, divided
  • ¾ teaspoon black pepper, divided
  • ¾ teaspoon dried thyme, divided
  • 2 garlic cloves, minced
  • 8 ounces jumbo pasta shells (about 24 shells)
  • 2 cups ricotta cheese
  • 1 egg
  • 2 cups grated Gruyère cheese, divided
  • ⅓ cup grated parmesan cheese, divided
  • 1 tablespoon all-purpose flour
  • 1 ½ cups vegetable broth
  • ⅓ cup heavy cream
  • ¼ cup breadcrumbs
  • 2 tablespoons chopped fresh parsley
Directions
  1. Melt the butter in a large oven-safe skillet over medium-low heat.
  2. Add the onions, 1 teaspoon salt, ½ teaspoon pepper, and ½ teaspoon thyme. Cook for about 45 minutes, stirring occasionally to prevent burning, until the onions are golden brown.
  3. When the onions are golden, stir in the garlic and cook for 2 minutes more. Then, turn off the heat and leave the onions in the pan.
  4. While the onions cook, bring a large pot of salted water to a boil.
  5. Cook the shells for 2 minutes less than the package instructions call for, until bendable but still firm in the center.
  6. Drain and spread the shells in a single layer on a baking sheet to cool.
  7. Preheat the oven to 400 F.
  8. Stir together the ricotta, egg, 1 cup Gruyère, half of the parmesan, and the remaining salt, pepper, and thyme in a large bowl.
  9. Stir ½ cup of the caramelized onions into the ricotta mixture.
  10. Fill each shell with the ricotta mixture, stuffing them full but not overflowing.
  11. Turn the heat to medium-low under the remaining onions in the pan and sprinkle in the flour. Cook, stirring frequently, for 1 to 2 minutes.
  12. Add the broth and cook for 5 to 6 minutes, stirring frequently, until the sauce thickens.
  13. Stir in the cream, then turn off the heat.
  14. Nestle the shells open side up in the sauce.
  15. Top the shells with the breadcrumbs, remaining Gruyère, and remaining parmesan.
  16. Bake until the cheese is browned and the sauce bubbles around the edges, 20 to 25 minutes.
  17. Sprinkle the shells with parsley before serving.