If the pumpernickel is not completely dry, put it on a baking sheet and bake in a 350° oven until it reaches the desired dryness.
Melt the butter in a large skillet and add the pumpernickel with 2 tablespoons of the sugar, cinnamon, ginger, cloves and hazelnuts. Caramelize and remove from the heat. Stir in the currants and set aside.
Preheat the oven to 375° and grease a 2-quart baking dish.
Thinly slice the apples and put them in a large saucepan. Add the wine, the remaining sugar and lemon zest and cook until apples are soft.
Spread a layer of apples on the bottom of the prepared dish and top with a layer of pumpernickel. Repeat until the apples and the pumpernickel are used up, ending with a layer of bread.
Bake for 30 minutes and serve warm with vanilla ice cream.