Heat 3 tbsp of olive oil in a large, shallow pan then tip in the pasta and stir, letting it turn gently golden in the heat of the oil. Add the sliced garlic, paprika and saffron and sizzle for 30 seconds, then add the tomato and 3/4 of the stock. Bring to a simmer and cook for 10 minutes, stirring occasionally. Add the peeled prawns, mussels and the rest of the stock and simmer for another 5 minutes. Taste and stir as you go, the pasta should be cooked but not mushy and the stock should be almost totally absorbed. Once the mussels are open and the prawns are pink, add the peas to heat through.