Preheat oven to 450F degrees. Spray a 9?9-inch baking dish with nonstick cooking spray.

In a medium bowl, mix together flour, sugar, and baking powder.

Pour in buttermilk and stir until a sticky batter forms. If the batter is too dry, add more buttermilk as needed.

Gently stir in diced ham and shredded cheddar cheese until combined.

In a microwave-safe bowl, melt salted butter. Pour melted butter into the prepared baking dish.

Pour biscuit dough into the baking dish on top of the melted butter, spreading it out evenly.

Cut the dough into 9 squares.

Bake on the middle oven rack for about 25-30 minutes, rotating the dish once during baking. Cover with foil if browning too quickly.

Check for doneness by inserting a toothpick; if it comes out clean, the biscuits are done. Slice and serve.