Preheat the oven to 425Fº (220Cº) with the rack adjusted to the upper middle position.
Add the flours, baking powder, baking soda, salt, and sugar to a deep bowl. Whisk to blend.
Using your fingertips, rub together quickly until it forms a sandy mixture with some pebble-sized pieces.
Scatter the butter pieces over the flour mixture. Using your fingertips, rub together quickly until it forms a sandy mixture with some pebble-sized pieces.
Add the cheese and meat to the bowl. Stir until well mixed.
Pour in the buttermilk, and stir just until there are no visible signs of flour, and it comes together into a wet, sticky dough.
Drop 1/4 cupfuls onto an ungreased baking sheet (I use an ice cream scoop to ensure evenly shaped biscuits). Bake for 15 to 17 minutes, until the biscuits are golden on the bottom. They’ll brown lightly on top, too, but it’ll be harder to notice since the buckwheat flour is dark. Let sit on the tray for 2 minutes, then serve warm.
Note: If baking smaller biscuits (I use a 1 1/2 tablespoon cookie scoop for this), start checking them around 12 minutes.