Preheat your oven to 350°F (175°C). In a medium saucepan, melt ½ cup of unsalted butter over low heat until fully melted. Carefully remove from heat and sprinkle ¾ cup of packed brown sugar evenly in a greased 9-inch round cake pan. Immediately arrange 2 cups of pitted cherries on top.

In a large mixing bowl, combine 1 ¾ cups of all-purpose flour, ¾ cup of unsweetened cocoa powder, 1 ½ cups of granulated sugar, 1 teaspoon of baking powder, ½ teaspoon of baking soda, and ½ teaspoon of salt. Whisk the dry ingredients together until well incorporated.

In a separate bowl, crack 2 large eggs at room temperature and beat them gently. Add 1 cup of buttermilk, ½ cup of vegetable oil, and 1 teaspoon of vanilla extract if using. Mix these ingredients thoroughly until fully combined.

Gradually add the wet mixture to the dry ingredients, stirring gently. Mix until just combined, then pour in ½ cup of hot coffee or water, mixing until the batter is smooth and glossy.

Pour the batter over the arranged cherries in the cake pan, spreading it evenly. Bake for 35-40 minutes. To check for doneness, insert a toothpick into the center; it should come out clean.

Once baked, remove the cake from the oven and let it cool in the pan for 10 minutes. Then, place a serving plate upside down on the pan and carefully flip the cake onto the plate.