Preheat your oven to 425°F (220°C).
In a large mixing bowl, whisk together flour, baking powder, baking soda, and salt.
Cut in the cold butter using a pastry cutter or your fingers until the mixture resembles coarse crumbs.
Gradually add buttermilk to the dry mixture, stirring until just combined.
Turn the dough onto a lightly floured surface and pat it into a rectangle about 1-inch thick.
Cut the dough into biscuits using a biscuit cutter and place them on a baking sheet lined with parchment paper.
Bake the biscuits in the preheated oven for 12-15 minutes, or until golden brown.
Meanwhile, in a large skillet, heat some oil over medium heat and sauté sliced onions until caramelized, about 10-12 minutes.
Add minced garlic and cook for another 1-2 minutes, then add the beef roast, broth, Worcestershire sauce, and pepper to the skillet.
Cover the skillet, reduce heat, and simmer for 2-3 hours until the beef is tender enough to shred.
Once the beef is cooked, remove it from the skillet and shred it, then return the meat to the skillet to soak up juices.
Serve the biscuits warm, topped with the shredded beef and a side of au jus for dipping.
