- 8 ounces kielbasa sausage, cut on diagonal into 1/2-inch-thick slices
- 4 cups coarsely grated Gruyère cheese (about 1 pound)
- 1 tablespoon plus 2 teaspoons cornstarch
- 1 cup hard apple cider
- 1 tablespoon apple cider vinegar
- 2 tablespoons Calvados, applejack brandy, or poire Williams (clear pear brandy)
- 2 Granny Smith apples, cored, cut into 1/2-inch-thick slices
- 1 baguette, cut into 3/4-inch cubes
- Preheat oven to 300°F. Heat heavy large skillet over high heat. Add kielbasa slices and sauté until browned on both sides, 2 to 3 minutes. Transfer to baking sheet and place in oven to keep warm.
- Toss cheese and cornstarch in large bowl to coat. Bring hard cider and vinegar just to simmer in medium saucepan over medium heat. Reduce heat to medium low (mixture should be barely simmering). Add a handful of cheese to simmering cider mixture. Stir until cheese is melted. Add remaining cheese 1 handful at a time, stirring until melted between additions. Increase heat to medium and cook until fondue begins to bubble, stirring constantly. Stir in Calvados. Season to taste with pepper.
- Transfer fondue to pot. Set fondue pot atop stand; light candle or canned heat burner. Arrange sausage slices, apple slices, and bread cubes in bowls alongside fondue pot.
- Alcoholic apple cider; available in the liquor department of most supermarkets and at liquor stores.