Directions
1. Preheat your oven to 375°F (190°C) and lightly grease a baking sheet.
2. Separate the biscuits and split each one in half horizontally to create two rounds.
3. Combine mayonnaise and horseradish sauce in a small bowl. Spread a thin layer of the mixture on the cut side of each biscuit half.
4. Place a few slices of roast beef and a sprinkle of Swiss cheese on the bottom half of each biscuit. Top with the other half of the biscuit, pressing gently to seal.
5. Place the prepared biscuits on the greased baking sheet and bake for 12-15 minutes, or until golden brown.
6. While the biscuits are baking, prepare the au jus by combining the gravy mix with 2 cups of water in a small saucepan over medium heat. Bring to a simmer, stirring frequently, until thickened.