In a large heavy stockpot, cook the bacon over medium-high heat until brown, about 5 minutes, stirring constantly. Remove the bacon from the stockpot and drain on paper towels. Add the onions and cook, stirring occasionally, for 5 minutes. Add the garlic and cook for 1 minute, stirring constantly. Add the oysters, the oyster liquor, cream, hot sauce, and Worcestershire sauce, and bring the mixture to a simmer. Once the mixture is hot and bubbly, add the cheese, whisking until melted. Remove the pot from the heat.
Using an immersion blender, or in batches in a blender, puree the ingredients, adding the spinach in batches as you puree. Season with the salt and white pepper, and stir in the liqueur. Pour the fondue into the fondue pot and garnish with the crumbled bacon. Serve hot with bread and crackers.
Yield: 4 servings