1. A day or two before you make the cake, toss the cherries in ¼ cup of rum. Cover and let macerate, stirring a few times.
2. To bake the cakes, butter two 9-inch (23cm) loaf pans and line the bottoms with parchment paper. Preheat the oven to 350ºF (180ºC).
3. Sift together the flour, cocoa, salt, baking soda, and baking powder. Set aside.
4. In the bowl of an electric stand mixer fitted with the paddle attachment, or by hand in a large bowl, beat the butter and sugar at medium-high speed until very light and fluffy, 3 to 5 minutes. Stir together the eggs and yolk with the vanilla in a small bowl, then dribble them in while beating at medium speed, stopping to scrape down the sides of the bowl to make sure they’re getting completely incorporated.
5. Mix in one-third of the flour and cocoa mixture, then half of the yogurt or buttermilk. Then mix in another third of the dry ingredients, then the rest of the yogurt. Finally add the remaining dry ingredients, and gently stir in the nuts, chocolate chips and cherries. (Which should have absorbed all the liquid. If not, add that as well.)
6. Divide and smooth the batter into the two prepared loaf pans and bake for 40 to 45 minutes, or until a toothpick inserted into the center just about comes out clean, but avoid overbaking it.
7. With a toothpick skewer, poke 50 holes in the cake and spoon 1/3 cup (80ml) of liquor over each cake. Let the cakes cool completely.