*Note: If you cannot find Caerphilly cheese, substitute cheddar.
In a medium saucepan, melt 2 tablespoons of the butter over medium heat. Add the flour and cook for 1 minute, stirring constantly. Slowly whisk in the beer. When the bubbles have begun to subside, add the cheeses, 1 handful at a time, stirring constantly and in 1 direction only, until smooth and creamy. Add 1 teaspoon of the Essence, the Worcestershire sauce, and the dry mustard and stir to combine. Keep warm while you prepare the oysters.
In a small skillet or saucepan, melt the remaining tablespoon of butter over medium-low heat and add the oysters. Cook for 1 1/2 to 2 minutes, or until the oysters are just cooked and have begun to curl around the edges, stirring occasionally. Season with the remaining 1/2 teaspoon of Essence.
To serve, divide the French bread toast between 6 plates, and divide the cooked oysters among the toasts. Top with the cheese mixture, and garnish with the crispy bacon.
Yield: 4 to 6 servings