Melt 10g of your butter in a saucepan and add your flour. Cook out for a couple of minutes until it starts to smell biscuity.

Gradually pour in 120ml of your Guinness, whisking all the while until you have a smooth sauce. Add your Worcestershire sauce, 1 tbsp of English mustard and your cheddar, then gently stir together until your cheese has melted and you have a thick mixture. Season with salt and pepper.

Pour your mixture into a container and chill in the fridge until ready to eat.

Peel, halve and finely slice your onions.

Melt your remaining butter in a frying pan. Tip in the onions and fry over a gentle heat for 15 minutes until softened.

Whack up the heat and keep cooking your onions until they are totally caramelised, stirring frequently to pick up any caramelisation from the pan. This will take about 15 minutes longer. Deglaze with your remaining Guinness if the onions needs a little more moisture - this will help the onions steam and soften.

Shred your lettuce, slice your gherkins and toast your burger buns in a dry cast iron pan.

Combine your mayonnaise with your remaining ½ tbsp of English mustard.

Heat your grill to high.

Get your cast iron pan or large frying pan heating on a high heat with a little vegetable oil.

Get your beef mince and gently shape it into 8 balls. Season the surface with salt and pepper.

Place a couple of your mince balls in the hot pan and pop a square of baking parchment on top of them. Place another heavy pan on top of the parchment to compress the burgers.

Fry for 2 minutes until the edges are going caramelised and crispy, then flip. Fry for two minutes on the other side. Repeat with your remaining patties.

Place your patties on a baking tray and put 2 tbsp of your rarebit mixture onto each. Grill for 2 minutes until the rarebit mix is bubbly and melted.

Assembly time. Spread a little mustardy mayo on the base and lid of your burger bun. Add some shredded lettuce to the base along with some pickles, then stack on two burger patties. Pop the lid on your burger and serve.