Preheat oven to 425F and line a medium sheet pan with parchment paper. Set aside.
In a large bowl, combine flour, baking powder, sugar, and salt. Use a pastry cutter or your fingers to work frozen shredded butter into flour mixture until crumbly.
Pour heavy cream and buttermilk over flour mixture and gently fold until a shaggy dough forms. Turn dough out onto a surface and gently knead several times until dough comes together.
Lightly flour surface and pat dough into a 1-inch thick square. Cut square into 4 pieces using a benchscraper or knife and stack the pieces on top of one another. Use your hands to flatten dough back down to 1 inch and use a 3-inch biscuit cutter to cut out biscuits
Place biscuits on prepared sheet pan so that they are touching each other. Place pan in the freezer for 15 minutes to chill the fats in dough before baking.
Remove biscuits from freezer and brush with additional heavy cream. Bake biscuits at 425F 13-16 minutes until golden brown.
Allow biscuits to cool slightly then serve warm with butter and jam if desired. Enjoy!