Creating these delicious Vegetarian Skillet Stuffed Shells is simple if you follow these steps:

1. Cook the Pasta: Boil a large pot of salted water. Add the jumbo pasta shells and cook until al dente, about 9-11 minutes. Drain and set aside.

2. Sauté the Vegetables: In a large skillet, heat the olive oil over medium heat. Add the chopped onion and garlic, sautéing until the onion is translucent, about 3-4 minutes.

3. Add More Veggies: Stir in the red bell pepper, zucchini, and chopped spinach. Cook until the vegetables are tender, approximately 5-7 minutes. Season with salt, pepper, basil, and oregano.

4. Prepare the Cheese Mixture: In a bowl, combine the ricotta cheese, half of the shredded mozzarella, grated Parmesan, and a bit of salt and pepper. Mix until smooth.

5. Stuff the Shells: Carefully fill each cooked pasta shell with the cheese mixture, using a spoon or piping bag if necessary. Set the stuffed shells aside.

6. Layer in the Skillet: Pour half of the marinara sauce into the skillet with cooked vegetables. Arrange the stuffed shells on top, then pour the remaining marinara sauce over them.

7. Add Cheese: Sprinkle the remaining mozzarella cheese on top of the shells for the final touch.

8. Simmer: Cover the skillet and let it simmer for 15-20 minutes over medium-low heat until heated through and bubbly. The cheese should be melted and golden.

9. Garnish and Serve: Remove from heat and garnish with fresh basil leaves, if desired.

These steps ensure a satisfying meal packed with both flavor and nutrition.