Turn on the grill to high. Line a baking
tray with foil, then place the meatloaf
slices on it. Cover with the tomato and
cheese, and grill until the meatloaf is hot
and the cheese has melted.
Warm the burger buns in the toaster
or under the grill. Mix the mayo and
harissa, then spread over the bottom
half of the buns, arranging the lettuce
and cucumber on top. Add the slices of
meatloaf, then top with the onion, a twist
of black pepper and bun tops.