Before starting, preheat your broiler to high. Wash and dry all produce. Add 10 cups water and 2 tsp salt to a large pot (use same for 4 ppl). Cover and bring to a boil over high heat. While water comes to a boil, core, then cut pepper into 1/4-inch slices. Halve, peel, then cut half the onion into 1/4-inch pieces (whole onion for 4 ppl). Roughly chop basil. Peel, then mince or grate garlic.

Add fusilli to the boiling water. Cook, stirring occasionally, until tender, 9-11 min. Reserve 1/4 cup pasta water (dbl for 4 ppl), then drain and return fusilli to the same pot, off heat.

While fusilli cooks, add peppers and 1/2 tbsp oil (dbl for 4 ppl) to a baking sheet. Season with salt and pepper, then toss to coat. Broil in the middle of the oven, stirring halfway through, until tender-crisp, 6-8 min.

While peppers broil, drain and rinse shrimp, using a strainer, then pat dry with paper towels. Heat a large non-stick pan over medium-high heat. When hot, add 1/2 tbsp oil (dbl for 4 ppl) then garlic, onions, Italian Seasoning and shrimp. Cook, stirring occasionally, until shrimp just turn pink, 2-3 min. Transfer shrimp to a plate.

Add crushed tomatoes, half the balsamic glaze (use all for 4 ppl) and reserved pasta water to the same pan. Season with salt and pepper. Add peppers, including any juices from the baking sheet. Cook, stirring often, until sauce thickens slightly, 5-6 min. Add shrimp and 2 tbsp butter (dbl for 4 ppl), then stir to combine.

Add shrimp sauce, spinach and half the basil to the pot with fusilli. Season with salt and pepper, then stir until spinach wilts, 1-2 min. Divide shrimp fusilli between bowls. Sprinkle Parmesan and remaining basil over top.