Preheat oven to 450℉ (230℃). Line your baking sheet with parchment paper or lightly grease it.
In a large bowl, whisk the flour, baking powder, baking soda, salt, and sugar.
Add the cold cubed butter to the flour mixture, and using a pastry cutter or fork, cut in the butter until the mixture resembles coarse crumbs.
Next, stir in the buttermilk and oil until just combined. The dough will be sticky and lumpy.
Scoop biscuits with a large ice cream scoop or a ¼ cup and drop them onto prepared baking sheets. Aim for similar sizes to ensure even baking.
Brush the top of the biscuits with some buttermilk.
Bake for 12-15 minutes or until golden brown on top. Rotate the baking sheet halfway through to ensure even browning.
Remove the biscuits from the oven and let them cool slightly on the baking sheet before transferring them to a wire rack to cool completely.
Serve immediately with butter, jam, or gravy.