Preheat the Oven: Start by preheating your oven to 350°F (175°C). Grease and line two 9-inch round cake pans with parchment paper.

Mix Dry Ingredients: In a large mixing bowl, sift together the flour, sugar, cocoa powder, baking powder, baking soda, and salt. This step ensures a light and fluffy cake.

Cream the Butter: In another bowl, beat the softened butter until creamy. Add the eggs, one at a time, followed by the vanilla extract. Mix until smooth.

Combine Wet and Dry Ingredients: Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk. Mix just until combined. Be careful not to overmix.

Add the Cherries: Gently fold in the pitted and halved cherries, distributing them evenly throughout the batter.

Divide and Bake: Pour the batter evenly into the prepared cake pans. Bake in the preheated oven for 25-30 minutes or until a toothpick inserted in the center comes out clean.

Cool the Cakes: Once baked, remove the pans from the oven and let them cool in the pans for about 10 minutes. Then, transfer them to a cooling rack to cool completely.

Prepare the Sauce: In a small saucepan, combine the cherries, sugar, cornstarch, water, and vanilla extract. Cook over medium heat until the mixture thickens and the cherries soften, about 5-7 minutes. Remove from heat and let it cool.

Beat the Frosting: In a mixing bowl, beat the softened butter until creamy. Gradually add the powdered sugar and cocoa powder, alternating with the milk and vanilla extract. Beat until fluffy and smooth.

Layer the Cake: Once the cakes are completely cool, place one layer on a serving plate. Spread a layer of chocolate frosting on top, followed by a generous amount of cherry sauce. Place the second cake layer on top.

Frost the Cake: Use the remaining chocolate frosting to cover the top and sides of the cake. Decorate with extra cherries if desired.