Prawn and avocado quinoa salad

Name: Prawn and avocado quinoa salad
Cuisine: British
Ingredients: 100g quinoa; 15g butter; 2 garlic cloves, finely chopped; 350g raw prawns with tail-shells on; 250g ripe tomatoes, cut into wedges; Bunch of fresh dill, chopped; Bunch of flatleaf parsley, chopped; 6 spring onions, finely sliced; 1 large ripe avocado, halved, stoned, peeled and sliced; 50g Kalamata olives, pitted and chopped; 2 tbsp extra-virgin olive oil, plus extra for drizzling; Juice of 1 lemon