Make the garlic-parsley butter: Puree the butter, parsley, shallots, lemon zest, roasted garlic and a little salt and pepper in a food processor until smooth.
Preheat the oven to 375 degrees F. Open the oysters with an oyster knife. Divide the oysters among small baking dishes lined with baguette slices. Place a heaping teaspoon of garlic-parsley butter on each oyster. Roast the oysters until the butter is melted, 8 to 10 minutes. Serve immediately.