Blackberry Jam Cake II recipe.

Ingredients
1 cup white sugar
2 tablespoons unsweetened cocoa powder
1/2 cup milk
1 teaspoon vanilla extract
1/2 cup butter
1 cup dark brown sugar
1 cup sour milk
1 teaspoon baking soda
2 1/2 cups all-purpose flour
1 1/4 cups blackberry preserves

Directions
Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 9x13 inch pan. In a saucepan, combine white sugar, cocoa, milk and vanilla. Cook over medium heat until smooth and thickened. Set aside to cool.
In a large bowl, cream together the butter and brown sugar until light and fluffy. Beat in the eggs one at a time, then stir in the cooked mixture. Combine sour milk and baking soda. Beat in the flour alternately with the sour milk mixture. Stir in blackberry jam. Pour batter into prepared pan.
Bake in the preheated oven for 45 to 50 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool.