In a small saucepan, warm the seafood stock and add the saffron threads to steep while you prepare the other ingredients.
Heat the olive oil in a small paella pan or wide skillet over medium heat. Add the diced chorizo and sauté for 2 minutes until the oils are released.
Add the diced onion and red bell pepper to the pan, cooking until softened, about 4 minutes. Stir in the minced garlic and smoked paprika, cooking for another 30 seconds until fragrant.
Add the rice to the pan and stir well to coat every grain in the flavorful oils. Season with sea salt and black pepper.
Pour the saffron-infused stock over the rice. Increase heat to bring to a boil, then reduce to a low simmer. Do not stir the rice from this point forward to allow the crust to form.
After about 10 minutes, when the rice is partially cooked, nestle the shrimp, mussels, and frozen peas into the rice.
Continue to simmer for 8-10 minutes until the liquid is fully absorbed, the shrimp are pink, and the mussels have opened. You should hear a faint crackling sound, indicating the socarrat is forming.
Remove from heat, cover with a clean kitchen towel, and let rest for 5 minutes. Garnish with fresh parsley and serve with a lemon wedge.