Tuna melt with ketchup

Tuna melt

• One 6-ounce (160 g) tin of tuna (preferred pole & line caught and MSC certified) in sunflower oil, drained
• 1 small red onion, diced
• 1 spring onion, white and light green parts, finely chopped
• ¼ bunch of flat-leaf parsley, leaves only, coarsely chopped
• 3 tablespoons mayonnaise
• Tabasco sauce
• 4 slices of bread, preferably rustic
• 1½ tablespoon (20 g) butter
• 4 slices of cheddar cheese
• Salt and pepper, to taste

Ketchup

• 2 tablespoons olive oil
• 1 garlic clove, minced
• 1 small red onion, diced
• One 14-ounce (400 g) can peeled plum tomatoes
• 1½ tablespoon tomato purée
• 1 tablespoon dark brown sugar
• 1 tablespoon red wine vinegar
• Salt and pepper, to taste