For the glaze:
To make the fruitcakes, in a small saucepan, bring the dried cherries and 1/3 cup (80 ml) kirsch or rum to a boil. Remove from the heat, cover, and set aside to macerate for about 1 hour.
Preheat the oven to 350°F (175°C). Butter the bottom and sides of two 9-inch (23-cm) loaf pans, dust them with flour, and tap out any excess. Line the bottoms with rectangles of parchment paper.
Into a small bowl, sift together the flour, cocoa, baking powder, baking soda, and salt. Set aside.
In a stand mixer fitted with the paddle attachment (or in a bowl by hand), beat together the butter and granulated sugar on medium speed until light and fluffy, 3 to 5 minutes.
In a small bowl, whisk together the eggs, egg yolk, and vanilla, then slowly beat this mixture into the butter mixture. Stir in half of the flour mixture, followed by the buttermilk or yogurt, then mix in the remaining flour mixture. Gently stir in the nuts, chocolate chips, and the macerated cherries along with any unabsorbed liquid.
Divide the batter between the prepared pans and bake until a toothpick inserted into the center of one comes out almost clean, about 45 minutes. (Some chocolate will likely cling to the toothpick.) Let cool for 15 minutes.
Poke each cake about 50 times with a toothpick then slowly drizzle each cake with 3 tablespoons (45 ml) of the remaining kirsch or rum. Let cool 30 minutes, then run a knife around the sides of the cakes to help loosen them from the pans.
Invert the cakes onto a wire rack, peel off the parchment paper, turn them right side up, and let cool completely.
To make the glaze, in a medium bowl, whisk together the powdered sugar and 6 tablespoons (90 ml) of the kirsch or rum. If it's too thick to spread (it should have the consistency of melted ice cream), whisk in 1 to 2 tablespoons (15 to 30 ml) more kirsch or rum. Spoon the glaze over the tops of the cakes, letting it run freely down the sides.
Let the glaze set until firm.
Storage: You can freeze the loaves after they cool, prior to dousing them with alcohol and applying the glaze. At room temperature, the cakes will keep for up to 5 days, wrapped in plastic. It's preferable to glaze them the day of serving.
Variation: Substitute an equal amount of any type of dried fruits, such as cranberries, raisins, or diced prunes, for the dried cherries. Or, 1 1/2 cups (750 g) drained Italian candied cherries make a flavorful substitute, too; because they're packed in syrup, they don't require soaking in kirsch or rum.
Tip: If you're serving the fruitcake to kids, you can soften the dried cherries in cranberry juice. Omit drizzling the cakes with liqueur and use water to make the glaze.
Reprinted with permission from Ready for Dessert: My Best Recipes by David Lebovitz, copyright © 2010. Published by Ten Speed Press, a division of Random House, Inc.