Preparation

In a medium-size saucepan, heat oil over high heat. Add garlic and vegetables, stirring a few times to coat, and turn heat down by half. Stir occasionally until vegetables start to release moisture (without browning), about 4 to 6 minutes.

For the roux, add butter and melt. Slowly add flour, whisking constantly, until flour is incorporated. Cook for 2 minutes, whisking constantly. Slowly add oyster liquor and cream, whisking until smooth. Turn heat to high and bring to a light boil, all the while whisking. Let the sauce thicken, about 1 minute. When sauce has thickened, adjust viscosity with water. This is the trickiest part. You need to use enough water to thin the sauce down and prevent scorching, but not so much that the sauce gets too thin. (Note: We used ½ cup.) Reduce heat and simmer, stirring regularly, until sauce is thick enough to liberally coat the back of a spoon, about 2 minutes. Turn off heat. Add bitters, herbs, salt, and pepper.

For the bread crumb mixture:

Combine bacon, Parmesan, and panko in a bowl and slowly add the melted butter, folding lightly with a spoon.

To complete:

Fill a baking pan halfway with rock salt as a bed for cooking the oysters, and heat in oven for about 15 minutes at 475ºF. (Preheating the prepared pan allows each oyster to cook with equal heat from below as well as above.)

Top each oyster with 1 tablespoon or more of sauce, and sprinkle with a generous amount of bread-crumb mixture. Transfer to prepared pan and bake in preheated oven until golden brown and slightly bubbling, about 7 to 10 minutes.

To serve:

Line two shallow bowls or rimmed serving plates with rock salt. Transfer oysters to the prepared plates, and serve with cocktail forks.