Melt the butter in a saucepan over a medium heat. Once foaming, tip in the flour and mustard powder and stir until a paste forms. Continue to cook for 2-3 mins until the paste turns darker. Splash in the Worcestershire sauce and a little of the beer. Stir and continue adding the beer slowly, stirring well after each addition, keeping the heat low to make sure the mix doesn’t boil.

Heat the grill to high. Remove the saucepan from the heat and stir through the cheese and lime pickle, continuing to stir until the cheese has melted. (You may need to return the pan to a low heat to completely melt the cheese.) Season with a pinch of pepper and set aside. Arrange the sliced bread on a baking tray and lightly toast both sides under the grill, 1-2 mins each side. Spread the cheese sauce over the top and grill for a further 3-4 mins until bubbling and browned. Leave to stand for 2 mins before serving with a green salad in a lemony dressing, if you like.