Methods 1) Mix the tomatoes, spring onions, celery and tuna in a small bowl. Add the mayonnaise and stir well. 2) Place the muffin halves on a grill with their cut-sides up. Grill until golden brown. Spoon the tuna mixture on to the muffins and then top with grated cheese. 3) Grill on low-medium for 10 minutes until the tuna mixture is warm and the cheese has melted. Makes six half muffins suitable for two hungry people.