Before starting, wash and dry all produce. Heat Guide for Step 6 (dbl for 4 ppl): 1/4 tsp mild, 1/2 tsp medium and 1 tsp spicy! 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. Add linguine to the boiling water. Cook uncovered, stirring occasionally, until tender, 10-12 min. Reserve 1/4 cup pasta water (dbl for 4 ppl), then drain and return linguine to same pot, off heat.

While linguine cooks, zest half the lemon (whole lemon for 4 ppl). Cut all the lemon into wedges. Using a strainer, drain and rinse shrimp, then pat dry with paper towels. Add shrimp and half the Italian Seasoning to a medium bowl. Season with salt and pepper, then toss to coat.

Heat a large non-stick pan over medium heat. When hot, add 1 tbsp oil (dbl for 4 ppl), then 1/4 tsp chili flakes (dbl for 4 ppl). Cook, stirring often, until fragrant, 30 sec. Carefully transfer to a small bowl and set aside.

Heat the same pan over medium-high. When hot, add 1/2 tbsp oil (dbl for 4 ppl), then shrimp. Cook, stirring occasionally, until shrimp just turn pink, 2-3 min.** Transfer shrimp to a plate. Add onions to the same pan. Cook, stirring occasionally, until onions soften, 2-3 min.

Add crushed tomatoes, reserved pasta water and remaining Italian Seasoning to the pan with onions. Cook, stirring occasionally, until sauce thickens slightly, 3-4 min. Season with salt and pepper. Remove the pan from heat. Add lemon zest, spinach and shrimp. Stir until spinach wilts, 1-2 min. Season with salt and pepper. Add tomato and shrimp sauce to the large pot with linguine. Toss to combine.

Divide shrimp diavolo between plates. Drizzle 1/4 tsp chili oil over each plate. (NOTE: Reference heat guide). Sprinkle Parmesan over top. Squeeze over a lemon wedge, if desired.