While the apples bake, make the biscuits. Whisk flour, baking powder, baking soda, salt and 3 tablespoons sugar together in a medium bowl. Add in cubed butter and shortening. Use a pastry cutter or fork to cut the fat in to the flour mixture. It shouldn't take long, you want there to be small, pea-sized chunks of fat distributed throughout the flour.
Once the fat is cut in, add half of the buttermilk. Use your fork to gently toss until evenly coated. Add the other half of the buttermilk and continue to stir until incorporated. DO NOT OVER MIX!
In a small bowl, mix together remaining sugar and cinnamon
Dump dough out on to a floured surface and use a rolling pin to gently form it into a (approximately) 6x8 rectangle. Sprinkle with a 1/3 of the cinnamon sugar mixture. Fold the dough in half over itself and roll or press into another rectangle the same size. Sprinkle with another 1/3 of sugar. Fold over again and sprinkle with remaining sugar. Fold once more time and then roll the dough out so it's about 1/4 inch inch tall.
Use a 2 1/2-inch biscuit cutter to cut 12 biscuits. If needed, reform scraps of dough to make all 12. Make sure you don't twist the biscuit cutter into the dough, just go straight down forcefully and straight back up. To prevent the cutter from sticking, dip in flour before you make each biscuit. Place the biscuits on a small baking sheet and place in the freezer until the filling is complete.
Once the apples have cooked for 45 minutes, remove foil and gently nestle biscuits on top. Brush with 1/4 cup of heavy cream. Bake in the oven for 12-15 minutes or until biscuits are golden brown and cooked.
While the biscuits cook, add remaining heavy cream and sugar to a small saucepan. Heat just until the sugar melts and keep warm over a low heat.
To serve: Scoop out apples and biscuits, then drizzle with warm sweet cream. (You could also serve with ice cream!)