Zesty Tuna Mayo Melt

Lightly toast the bread and arrange in a single layer on a baking sheet.

Preheat the oven to grill.

Mix the mayonnaise and lemon zest in a mixing bowl.

Fold in the tuna flakes, red onion, gherkin and tomato and 60g of the mozzarella cheese.

Divide the mixture between the slices of toast.

Grind some black pepper over the mixture and top the open sandwiches with the remaining45g of mozzarella cheese.

Grill for 3-4 minutes, or until the top is melted, golden and bubbling.

Serve at once.