Preparation

Before diving into the cooking process, ensure all ingredients are prepped and ready for use. Finely slicing the leek and grating the cheddar cheese ahead of time reduces complexity and eases the cooking flow. Gathering tools such as a saucepan, a whisk, and a grill are also necessary for a seamless cooking experience.

Cooking Process

Step 1: Prepare the Cheese Sauce

In a medium saucepan, melt the margarine over low heat. Stir in the plain flour to form a smooth paste. Allow this mixture to cook on a gentle heat for about 1 to 2 minutes, ensuring it doesn't brown.

Step 2: Incorporate the Liquid Ingredients

Gradually pour in the ale, whisking continuously to eliminate any lumps. Increase the heat slightly, bringing the mixture to a simmer. Add the mustard powder and Worcestershire sauce, stirring thoroughly to combine the flavors.

Step 3: Add the Cheese and Seasoning

Reduce the heat again and add the grated cheddar cheese, stirring until fully melted and the sauce is velvety smooth. Season with salt and pepper. Remove from heat and quickly beat in the egg yolk to enrich the sauce further.

Step 4: Sauté the Leeks

In a small pan, melt butter and add the sliced leek. Sauté over medium heat until soft and slightly caramelized, which takes about 5-7 minutes. Season with a pinch of salt and pepper.

Step 5: Assemble the Dish

Preheat the grill to medium-high. Lay the slices of brown bread on a baking sheet. Distribute the sautéed leek evenly across each slice. Pour the cheese sauce generously over the top, ensuring each slice is fully coated.

Step 6: Grill

Place the baking sheet under the preheated grill. Grill until the sauce is bubbling and golden brown on top, approximately 5 minutes. Keep a watchful eye to prevent burning.

Serving Suggestions

Once done, remove from the grill and garnish with fresh thyme sprigs. Serve hot as an appetizer or a main dish accompanied by a green salad. For an authentic culinary journey, pair your meal with a pint of ale or a refreshing glass of cider. Enjoy the whimsically rich flavors and tradition-filled experience of this delightful Welsh classic.

Don't forget to set a