Make the saffron-infused stock: Heat 2 teaspoons olive oil in a saucepan over medium heat. Add reserved shrimp shells and cook for 1-2 minutes until pink and fragrant. Stir in saffron threads, then add chicken broth. Bring to a simmer and cook for about 20 minutes until the broth develops a rusty brown color. Strain and set aside.

Prepare the sofrito base: In a large paella pan or wide skillet, heat 2 tablespoons olive oil over medium-high heat. Sauté the onion and bell pepper for 5 minutes until softened. Add garlic and cook for 30 seconds until fragrant.

Add the chorizo: Stir in the sliced chorizo and cook for 2-3 minutes until it begins to release its oils and flavor.

Toast the rice: Add the rice to the pan and stir to coat with the oils. Cook for 1-2 minutes until the grains become slightly translucent at the edges.

Add seasonings and broth: Stir in the smoked paprika and salt. Pour in the saffron-infused broth and bring to a boil. Reduce heat to maintain a gentle simmer.

Let it cook undisturbed: Allow the paella to cook without stirring for about 15-18 minutes, or until most of the liquid is absorbed.

Add the shrimp and peas: Arrange the shrimp on top of the rice and sprinkle with peas. Continue cooking for 5-7 minutes until the shrimp are pink and cooked through.

Create the socarrat: For the signature crispy bottom layer, increase heat to medium-high for the final 1-2 minutes, until you hear a slight crackling sound, indicating the bottom is crisping.

Rest and garnish: Remove from heat, cover with a clean kitchen towel, and let rest for 5 minutes. Garnish with chopped parsley and serve with lemon wedges.