Before starting, 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, halve tomatoes. Zest lemon, then cut into wedges. Peel, then cut half the onion into 1/4-inch pieces (whole onion for 4 ppl). Peel, then mince or grate garlic.

Heat a large non-stick pan over medium heat. When hot, add pepitas to the dry pan. Toast, stirring often, until golden-brown, 4-5 min. (TIP: Keep your eye on them so they don't burn!) Remove the pan from heat, then transfer pepitas to a plate and set aside.

Return the same pan to medium. When hot, add 1/2 tbsp oil (dbl for 4 ppl), then onions. Cook, stirring occasionally, until softened, 2-3 min. Add tomatoes and garlic. Cook, stirring occasionally, until tender, 2-3 min. Season with salt and pepper.

Meanwhile, add ravioli to the boiling water. Cook, stirring occasionally, until tender, 2-3 min. Reserve 1/4 cup pasta water (dbl for 4 ppl), then drain. Add 1 tbsp butter (dbl for 4 ppl) to the pot. Gently toss to coat.

Add pesto and reserved pasta water to the pan with veggies. Cook, stirring occasionally, until sauce thickens slightly, 2-3 min. Season with salt and pepper. Add spinach, half the Parmesan, 1/4 tsp lemon zest and 2 tbsp butter (dbl both for 4 ppl). Remove the pan from heat, then stir until spinach wilts, 1 min. Add ravioli. Gently stir to coat.

Divide ravioli between bowls. Sprinkle with pepitas and remaining Parmesan. Squeeze a lemon wedge over top, if desired.