Preheat oven to 325. In a large bowl, combine the flour, cocoa powder, baking soda, and salt. Set aside.
In a large mixing bowl, cream together the butter and sugar on medium high for five minutes. Beat in the eggs, one and time, until completely incorporated. Add the sour cream, milk, food color and vanilla and mix slowly until combined.
Add the dry ingredients in batches, mixing until just combined. Do not overmix.
Spoon into mini bundform pans, place on a baking sheet, then bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean. Place on a cooling rack for 10 minutes, then remove from pan and allow to cool completely.
While the cake is cooling, beat together the cream cheese, butter, and vanilla until light and fluffy. Slowly beat in the powdered sugar until thoroughly combined. Very slowly add the milk, tablespoon by tablespoon, until it reaches a pourable consistency, between 1/4 and 1/2 cup, in general.