Preheat the oven to 400 degrees F, and bring a pot of salted water to a boil.

Add the clams to the boiling water, cover, and cook for about 6 to 8 minutes or until the shells open. Discard any shells that do not open. Remove the clams from the pot and place on a parchment-lined sheet pan. When the clams are cool enough to handle, gently pry the shells apart enough to remove the clam, leaving the hinge attached. Loosen the muscle in the lower shell and remove the clam from the shell. Save the 6 nicest shells and place the shells on a parchment-lined baking sheet and set aside. Finely chop the clam meat and set aside.

In a mixing bowl, stir the butter and 1 tablespoon of the garlic together. Season the butter with salt and pepper. Spoon the butter onto a piece of plastic wrap. Form the butter into a 1-inch log, cover tightly, and place in the refrigerator. Refrigerate for 1 hour.

Heat a saute pan over medium-high heat. Add the chorizo and cook until rendered, about 2 minutes. Add the onions, celery and peppers. Season lightly with Essence. Cook for 2 more minutes. Stir in the remaining garlic, the breadcrumbs, and reserved clam meat and remove from the heat. Stir in the reserved cooking liquid and 2 tablespoons of the parsley. Season with Essence and cool slightly.

Pack the stuffing mixture into one side of each shell. Slice the compound butter into 6 equal slices. Place a slice of the butter on top of each stuffing mixture. Using your hands, pat the stuffing firmly into each clam shell. Top each evenly with the cheese and the remaining parsley. Close the shells as tightly as possible and wrap with aluminum foil or tie the shell tightly with butchers twine.

Bake for 15 to 20 minutes. Unwrap the clams and place on a serving platter. Garnish with additional parsley and Essence and serve hot.