In a large bowl, stir together the flour, baking powder, sugar, salt, and lemon zest. Cut the cold butter into small cubes, and cut into the flour mixture using a pastry cutter or your hands until the mixture resembles very coarse crumbs.
Slowly work in the heavy cream until a shaggy dough forms. Turn onto a floured surface. You'll need to knead the dough a little to form a roll-able dough. Working quickly, pat the dough into a disk about 1/2 inch thick. Cut into 4 sections, and stack each section on top of eachother.
Roll this into a large rectangle, about 1/4-1/2 inch thick. Using a small round or square cutter, cut about 30 (or more if you can) biscuits out of the dough. You should use a cutter about 1 inch in size.
Move the cut biscuits onto a plate, and place in the fridge while you make the filling.
Preheat the oven to 400 degrees. In a large bowl, stir together all the ingredients for the filling until no dry spots of cornstarch remain.
Pour the filling into a shallow baking/casserole dish that holds about 2 quarts. This would be about a 9 inch square baking pan for reference (or you can use this exact kind of pan if it's all you have!)
Place the chilled biscuits over the top of the filling, as close together as you can- some overlap is okay- covering all of the filling in the pan. Brush the tops of the biscuits with the melted butter generously, and top generously with the coarse sugar.
Place your baking dish on top of a sheet pan to catch any juice that spills over. Bake for 25-30 minutes, or until the biscuits are deeply golden brown, and the juices of the fruit are bubbling and hot. Cool slightly, and serve warm with vanilla ice cream! It's a MOOD.