2 c. unbleached all-purpose flour, plus more for dusting (gluten-free flour also worked fine)
1 tsp. salt
4 tsp. baking powder
1/2 tsp. cream of tartar
1 tbsp. sugar
1/2 tsp cayenne pepper
1 stick unsalted butter
1 c. grated sharp cheddar cheese
2/3 c. milk, preferably 2%
Heat oven to 425 degrees. Thoroughly combine dry ingredients in a large bowl. Cut butter into pieces and work into flour mixture with fingers until dough resembles coarse meal. Stir in cheese.
Make a well in center of flour mixture, pour in milk, and stir just until dough comes together. Do not overmix or the oven gnomes will exchange your biscuits for biscuit-sized rocks. Turn dough onto a lightly-floured surface and knead gently 10 to 12 times. Pat dough into a circle about 1/2 inch thick. Cut out biscuits using a 2" circle cutter (I used an inverted glass; you could also just cut the big square of dough into biscuit-sized squares, if you wanted). Do not twist cutter. Transfer biscuits to a lightly-buttered baking sheet and bake in center of oven until brown, approximately 12 to 15 minutes. Serve hot.
I added about 1/4 c. chopped fresh dill to this mixture. I think chives would also go well. Also, I realize 1/2 tsp. cayenne doesn't seem like enough to spice up that much dough, but the biscuits were much spicier than I anticipated.