Cheesy Tuna Melt with Onions

Method

1. Drain the tuna and mix with mayonnaise and Dijon mustard.
2. Add shredded cheddar cheese and sliced onions to the tuna mixture.
3. Butter both sides of the bread slices.
4. Place the tuna mixture between two slices of bread and top with the remaining bread slices.
5. Cook on a skillet over medium heat until the cheese is melted and the bread is golden.
6. Cook fish and seafood to an internal temperature of 63°C (145°F) before serving.