Welsh Rarebit

Set a small saucepan over medium heat. Add the butter, and once it melts, add the flour and whisk well. Continue whisking and let the flour cook for about a minute, until the mixture turns slightly golden and begins to smell slightly nutty, about 1 to 2 minutes. This will allow the raw flour taste to cook out.

Add the mustard powder, paprika, and 1 teaspoon of Worcestershire sauce. Whisk well and cook for about 30 seconds. Slowly pour in the beer little by little, whisking constantly, until the mixture is smooth and thick, about 2 minutes.

Add the cheddar in small increments, whisking constantly, until all the cheese is melted and the sauce is smooth. It will be very thick and look about the color of milky coffee.

With the pan off the heat, whisk in the egg yolk until a smooth sauce comes together. If, after adding the yolk, it has the consistency of wet sand, don't fear. It'll still melt smoothly under the broiler. Set aside.

Meanwhile, toast bread lightly on both sides in a toaster, toaster oven, air fryer, or under the broiler.

Evenly spread a thick layer of sauce on each of the toasts, being sure to spread all the way to the edges so that the toast doesn't burn.

Set the oven rack about 5 inches from the broiler element. Preheat the broiler. Broil the rarebits until the sauce is browned in spots and bubbling, 2 to 3 minutes.

With a spatula, transfer each rarebit to a plate. With the back edge of a butter knife, press into the rarebit slightly–diagonally in one direction, then diagonally in the opposite direction–to make the traditional crosshatch pattern. Sprinkle rarebits with remaining Worcestershire sauce, if desired, and serve immediately.