Whip up the stuffing a day ahead and these baked oysters will come together in a cinch. When it comes time to plate, serve them on a bed of rock salt.
Preheat oven to 425 degrees. In a large sauté pan, cook bacon until crispy, then transfer to a paper towel-lined plate. Drain off fat, reserving 2 tablespoons.
In the same pan over medium heat, add the 2 tablespoons bacon fat and sauté leeks. Add celery and cook for 2 minutes, stirring frequently. Stir in white wine and let reduce by two-thirds. Add cream and bring to a boil. Reduce heat to low and simmer for 1 minute. Add parmesan and chives; season with salt and pepper.
Spoon about 1½ teaspoons of the mixture onto each oyster and top with breadcrumbs. Bake until breadcrumbs are golden brown, 5 to 8 minutes, then serve immediately.