01 - Preheat oven to 375°F. Grease a 9-inch pie dish or deep baking dish with nonstick spray or butter.
02 - Bring a large pot of salted water to a rolling boil. Add spaghetti and cook until just al dente, about 8 minutes. Drain well and set aside.
03 - Heat a large skillet over medium heat. Crumble in the Italian sausage and cook, breaking it apart with a wooden spoon, until fully browned and no pink remains. Drain off any excess fat.
04 - Add the diced onion, chopped bell pepper, minced garlic, and diced jalapeños to the skillet with the sausage. Sauté for 4 to 5 minutes, stirring occasionally, until the vegetables are softened and fragrant.
05 - Stir in the marinara sauce, tomato paste, crushed red pepper flakes, dried oregano, and smoked paprika. Season with salt and black pepper to taste. Bring to a gentle simmer and cook for 5 minutes, allowing the flavors to meld.
06 - In a large mixing bowl, combine the drained spaghetti, ricotta cheese, beaten eggs, and chopped fresh basil. Toss thoroughly until every strand of pasta is evenly coated with the ricotta mixture.
07 - Transfer the spaghetti mixture into the prepared pie dish, pressing it evenly across the bottom and up the sides to form a crust layer. Spoon the sausage and vegetable sauce over the spaghetti base, spreading it into an even layer. Sprinkle the shredded mozzarella and grated Parmesan evenly over the top.
08 - Place in the center rack of the oven and bake for 25 to 30 minutes, or until the cheese is fully melted, bubbling, and golden brown in spots.
09 - Remove from the oven and let the pie rest for 10 minutes to set before slicing. Garnish with additional fresh basil and serve warm.