Melt 2 tablespoons of the butter in a medium skillet over medium-high heat. When the butter begins to foam, add the parsley, garlic, lemon juice, and Worcestershire. Cook for 2 minutes until slightly reduced. Add the cream and cook, whisking, for 15 seconds. Season with salt and cayenne. Turn heat down to low and whisk in the remaining butter, 1 tablespoon at a time, adding each piece before the previous one has been completely incorporated. Continue until all the butter is incorporated and the sauce coats the back of a spoon. Immediately remove the pan from the heat to prevent the sauce from getting too hot and breaking.