The Hairy Bikers' crayfish macaroni cheese recipe

INGREDIENTS

• 100 butter, plus extra for greasing
• g dried macaroni or other short pasta shapes
• 250 small onion, finely chopped
• g chorizo or andouille sausage, skinned and diced
• 1 cayenne pepper
• 50 paprika
• g ground nutmeg
• 0.25 plain flour
• tsp milk
• 0.5 mature Cheddar cheese, coarsely grated
• tsp Gruyere, coarsely grated
• 0.25 dry white breadcrumbs
• tsp peeled and cooked crayfish tails, thawed if frozen