Tuna Melt

Ingredients (11)

• 20 oz tuna
• 1 medium onion
• 1/2 stalk celery
• 1 clove garlic
• 1 tbsp parsley
• 5 tbsp mayonnaise
• 3 tbsp olive oil
• 1/2 cup mozzarella
• salt and pepper
• 12 slices bread
• softened butter