How to Make It
Preheat oven to 475°F. Stir together flour and pepper in a large bowl. Add cheese and butter and, using your fingers or a pastry cutter, work butter into flat pieces, tossing mixture as you work to ensure all pieces are coated with flour. Add ham and toss to coat. Using a fork, stir in buttermilk just until dough comes together.
Line 2 baking sheets with parchment paper. Scoop dough into 1½-inch balls, and place 1½-inches apart on prepared baking sheets; flatten each ball slightly. Bake, rotating halfway through, until edges begin to brown, 12 to 14 minutes.
Prepare the honey mustard: Whisk together Dijon, mayonnaise, honey and horseradish in a small bowl. Serve with biscuits.