Whisk together flour, sugar, baking powder, and salt in a large bowl. Add butter to the bowl and cut into the flour with a pastry blender until the largest pieces of butter are about the size of a pea and the flour mixture resembles coarse meal. Stir in ¾ cup of heavy cream, lemon juice, and orange and lemon zests.. Press dough together between the palms of your hands. If it doesn't just hold together, add more heavy cream until is just holds together.
Preheat oven to 400º F. Line a rimmed baking sheet pan with parchment paper or a nonstick baking sheet.