My best friend turns 60 today and I wanted to bake her a special cake. She adores strawberries and blueberries so I threw this together for her. It takes a bit of time to put together but is well worth the effort!
After cake has cooled on racks (about 30 minutes), place in freezer while you prepare the filling and whip the cream.
Add strawberries, blueberries, sugar and tapioca starch to food processor or blender. Chop on high for about a minute or until thoroughly blended.
Note: if you can't find tapioca starch, you can buy minute tapioca and grind it up in a spice or coffee grinder and use it as the starch. Set aside till needed.
To your mixer, add heavy cream, vanilla, 1T. sugar, and tapioca starch and whip till medium peaks form. Place in refrigerator till needed.
Remove cake from freezer and cut each layer in half.
Place 1st half layer on cake plate. Fill a pastry bag with whipped cream, and pipe it around edge. fill with berry mixture. Repeat until you have 3 half layers edged with whipped cream and filled with berries.
Place final half layer on top, pipe whipped cream around edge. Then starting on the edge, pipe whipped cream in a curved line, stop in the center of cake. continue till you have five curved lines ending in the center. Carefully fill the spaces in between with berry mixture. Spread or pipe remaining whipped cream on the sides of cake.