In a small bowl, soak the saffron threads in 2 tablespoons of warm seafood stock and set aside.
Heat the olive oil in a large paella pan or wide, shallow skillet over medium heat.
Add the chopped onion and diced red bell pepper to the pan and sauté for 5 minutes until softened.
Add the minced garlic and smoked paprika, stirring for 1 minute until fragrant.
Add the rice to the pan and stir to coat the grains with the oil and vegetables for 2 minutes.
Pour in the diced tomatoes and the saffron-infused stock along with the remaining seafood stock. Stir to combine and bring to a boil.
Reduce heat to medium-low and simmer uncovered for 15 minutes without stirring.
Arrange the shrimp, mussels, squid rings, and clams evenly over the rice. Continue cooking for another 15 minutes until the rice is tender and the seafood is cooked through. Discard any mussels or clams that do not open.
Scatter the frozen peas over the paella during the last 5 minutes of cooking.
Season with salt and freshly ground black pepper to taste.
Remove the pan from heat and cover loosely with foil. Let the paella rest for 5 minutes.
Sprinkle chopped fresh parsley over the top and serve with lemon wedges on the side.