Boil a large pan of salted water. tip in spaghetti, then cook for 7 minutes. add frozen peas, then cook for 3 minutes more until both are cooked through.
Drain in a colander, reserving a little cooking water, then tip back into the pan with white crabmeat from 2 × 170g tins and 5 tbsp half-fat crème fraîche. Stir well with 1 chopped red chilli, a handful of chopped parsley and the zest and juice of 1 lemon. Add a little of the cooking water if too dry.