Some time ago there was a thread, looking for a recipe possibly?
I can't recall, but whatever the case:
Bon Appetit has a recipe for one in this month's issue (June), one with raspberries and blueberries (p 93) - cream cheese frosting. It's not on their site. I made it over the weekend and it was a huge hit -- people took a few pieces to home to freeze, they loved it so much. And it did call for the use of red food coloring (1 tbs.)
If anyone wants the recipe, just ask -- I'll posted it here, edited of course.