Preheat oven to 425°F. Add the self-rising flour and butter to a bowl.
Use a pastry cutter to cut the butter into flour and work until the butter resembles small peas.
Pour 2/3 cup of buttermilk into the flour mixture. Stir until the dough starts to pull from the sides. If the dough is dry, add more buttermilk as needed.
Turn the dough out onto a board dusted with all-purpose flour. Pat out into a rectangle, about 1/2-1/4 inch thick.
Use a round cutter or cut with a sharp knife into a circle.
Place on a baking sheet lined with parchment paper. Bake in the oven for 10 to 14 minutes.
To make the honey cayenne butter, add the butter, honey, salt, and cayenne to a bowl.
Mix until combined. Taste and check for seasoning. Add to a ramekin or wrap in plastic wrap and keep in the fridge until ready to use.
Serve the biscuits warm with honey cayenne butter. Drizzle more honey over if desired.