Place rack in upper third of oven and preheat to 450 degrees F
To make biscuits: In a food processor with the metal blade or in a medium bowl with a fork or pastry blender, combine flour, baking powder, soda, cocoa, salt and sugar. Add butter and pulse or mix until it's the consistency of coarse meal. Add chocolate chips and buttermilk and mix until moistened and dough begins to hold together. Do not make into a ball.
Turn out onto a floured board; dough will be sticky. Knead 5 times and pat into a 1-inch thick circle. Cut out 4 biscuits with a floured 2" heart-shaped cutter. Place on ungreased cookie sheet. Bake for 12 minutes.
Hull and quarter berries; toss with sugar. Set aside.
Whip cream until soft peaks form. Add sour cream, sugar and vanilla, beating until soft peaks form.
To assemble: Split biscuits. Place bottom half on plate. Top with berries and cream. Place half biscuit on top. Drizzle with fudge sauce. Serve immediately.