In a medium skillet over medium heat, melt butter. Add onions and cook until lightly browned and soft (about 15 minutes). Set aside.

Preheat the oven to 400°F. Line a large baking sheet with parchment paper.

Separate each biscuit into two pieces, making a total of 16 pieces. Roll each out to about 4 inches wide. Place 8 of the biscuit halves on the lined baking sheet.

Divide the roast beef and cooked onions evenly over each of the 8 biscuit halves on the baking sheet. Top each with 4 of the quarter pieces of provolone cheese, stacking them slightly. Then, place the remaining biscuit halves on top to form a sandwich. Press the edges of the dough together to seal slightly.

Brush the beaten egg over the tops of the biscuits.

Bake for 15-17 minutes, or until the biscuits are golden brown.

While the biscuits are baking, add beef consomme to a medium saucepan over medium heat. Cook until heated through (about 3-5 minutes).

Serve the baked biscuits with the warm beef consomme on the side for dipping.