Preheat the oven to 400°F.
In a large skillet over medium-high heat, heat 1 tablespoon of the olive oil. Add the sausage and cook, stirring, until the meat is browned and all the pink has disappeared, about 4 minutes. Add the onions and cook, stirring, for 2 minutes. Stir in the garlic, salt, and black pepper. Remove from the heat and pour into a medium-size mixing bowl. Let cool to room temperature.
In another medium-size mixing bowl, combine 2 tablespoons of the olive oil, the bread crumbs, parsley, cheese, and Creole seasoning. Mix well. Add the sausage mixture and mix well. Combine the oyster liquor and enough water to make a total of 1 1/4 cups of liquid. Add this to the bread crumb-and-sausage mixture and mix well.
Grease the bottom of a 10-inch pie pan with the remaining 1 tablespoon olive oil. Arrange the oysters in one layer in the bottom of the pan. Cover the oysters evenly with the sausage mixture, packing it firmly down onto them.
Bake on the center rack of the oven until the top is golden brown, 18 to 20 minutes. Remove from the oven and serve hot.
Yield: 8 appetizer servings