This was the cake we had for my birthday. Mostly chocolate with a subtle cherry flavor.
1 Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9×13 inch pan. In the top of a double boiler, heat chocolate, stirring occasionally, until chocolate is melted and smooth. Remove from heat and allow to cool to lukewarm.
2 In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the eggs one at a time, then stir in the yogurt, melted chocolate and cherries with juice. Stir together the flour and baking soda and beat into the creamed mixture alternately with the sour milk. Pour batter into prepared pan.
3 Bake in the preheated oven for 30 to 40 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool.