Preheat the grill to high. Lightly oil a foil-lined baking tray and arrange the 4 largest slices of white sourdough bread on it. Grill for 1-2 mins each side to lightly toast. Tip four cheese sauce into a small pan and heat gently until bubbling.

Meanwhile, spread 2 of the toast slices with 1 tsp each wholegrain mustard. Divide leftover sliced turkey and 4 cooked, sliced leftover pigs-in-blankets between the bases, then add 1 heaped tbsp cranberry sauce and 2 chopped cornichons (optional) to each.

Cover each with the grated Gruyère. Add 2 tbsp warm cheese sauce to each; sandwich together with the remaining toast and lightly press down. Spoon the remaining cheese sauce over the sandwich tops, then scatter each with another 20g grated Gruyère. Season with black pepper. Grill for 3-5 mins or until bubbling and golden. Transfer to a board and slice in half to serve.