In a large bowl whisk together all dry ingredients: flour, baking soda, baking powder, salt and cream of tartar.

Add in the cold chunks of butter and mix in with a pastry cutter (or with your fingers) until small pea size bits form.

In a separate bowl whisk together the buttermilk, 3/4 of the heavy cream and the egg.

Slowly pour in the wet to the dry ingredients.

Mix briefly to combine. Do not over mix, the mixture will be slightly wet.

Turn out mixture onto a lightly floured surface and knead the dough with your hands until the dough comes together.

Using your hand or a floured rolling pin press dough out into the shape of a 4×8 rectangle.

Using the long ends of the rectangle, fold the dough into thirds.

Turn the dough 90 degrees and roll out into another 4×8 rectangle.

Repeat folding it into thirds.

Gently roll out until it is about 1 inch thick.

Using a 3″ round cookie cutter, cut out circles from the dough. You may need to flour the biscuit cutter before each cut. Do not twist while cutting each circle, just press down to cut.

Lightly grease a sheet pan. Place the biscuits about 1 inch apart.

Using a pastry brush, lightly brush the tops of the biscuits with the remaining heavy cream.

Preheat oven to 425 degrees.

Chill the unbaked biscuits on the pan in the fridge for 10 minutes while the oven is preheating.

Bake for 15-18 minutes or until edges are golden brown and the middle is cooked through. Biscuits should puff up almost double their original size.

Serve warm. Cooled biscuits can be stored in an airtight container for 3 days.