Before starting, preheat the oven to 450°F. 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. Meanwhile, roughly chop spinach. Peel, then cut onion into 1/4-inch pieces. Thinly slice basil. Zest, then juice half the lemon (whole lemon for 4 ppl). Cut any remaining lemon into wedges. Peel, then mince or grate garlic. Drain and rinse beans.

Add tomatoes, 1/4 tsp lemon zest and 1 tbsp oil (dbl both for 4 ppl) to a parchment-lined baking sheet. Season with salt and pepper, then toss to coat. Roast in the middle of the oven until tomatoes burst, 12-15 min.

Meanhwhile, add rigatoni to the boiling water. Cook, stirring occasionally, until tender, 10-12 min. Reserve 1/2 cup pasta water (dbl for 4 ppl), then drain and return rigatoni to the same pot, off heat.

Meanwhile, heat a large non-stick pan over medium heat. When hot, add 1 tbsp butter (dbl for 4 ppl), then onions, garlic and 1/2 tsp lemon zest (dbl for 4 ppl). Cook, stirring occasionally, until onions soften, 3-4 min. Remove the pan from the heat, then add half the basil and 1/2 tbsp lemon juice (dbl for 4 ppl). Season with salt and pepper, to taste, then stir to combine.

Add reserved pasta water, beans, sun-dried tomato pesto, onion mixture and spinach to the pot wit rigatoni. Toss until spinach wilts and rigatoni is coated, 1-2 min. Season with salt and pepper, to taste.

Divide pasta between plates. Top with the roasted tomatoes. Sprinkle Parmesan and remaining basil over top. Sprinkle with chili flakes, if desired.