Quick Prawn Coconut Curry

Name: Quick Prawn Coconut Curry
Cuisine: Asian, Indian
Ingredients: 225g prawns (I used frozen); 1/2 cup (100g) frozen peas; 1/2 400ml can coconut milk; 1 tbsp coconut oil (or any oil); 1 medium onion, chopped; 1-2 garlic cloves, minced; 1 tsp paprika; 1 tsp cumin; 1 tsp turmeric; 1 tsp garam masala; 1 tsp coriander; 1 tsp mustard seeds (optional); 1 tsp cumin seeds (optional); 1 lemon (the juice only); salt and pepper to taste; handful of fresh parsley, finely chopped