Heat a griddle pan to hot and butter the bread on both sides. Fry the slices on each side and fry your bacon lightly if you are using it.

Heat up your grill and set your oven rack about a quarter of the way down.

Make your sauce by melting the butter in a small to medium-sized heavy-based pot and add the flour. Cook until you have a dry paste over low heat.

Add the stout in parts whisking all the time. Add the milk, mustard, Worcestershire sauce and whisk while cooking for a few minutes until you have a thick sauce.

Add the cheese and allow it to melt completely.

Place your toasted bread on an oven tray and top with a slice of bacon. Divide the sauce amongst the slices of bread ensuring you have a fairly generous layer and smooth it to over the surface.

Place under the grill and cook until bubbling.