Adjust the oven rack to the middle position. Preheat the oven to 450°F.
In a medium bowl, whisk together flour, baking powder, baking soda, salt, and sugar.
Cut 1 cup of butter into ½-inch cubes. Add butter into the flour mixture and toss to coat.
Use fingers to break the butter into small pieces in the flour until the mixture resembles cornmeal.
Gradually add 1 cup buttermilk into the flour mixture, stirring with a fork until incorporated.
Knead the biscuit mixture in the bowl 5 to 6 times until a shaggy dough forms.
Lightly dust working surface with the flour. Turn the mixture onto the floured surface, knead a few times and shape into a 1-inch thick square, about 8 x 8 inches.
Cut the dough into 4 even-shaped squares and stack as evenly as possible on top of each other.
Lightly flour a rolling pin and roll the dough out into a 3/4-inch thick square, 9 x 9 inches.
Using a 3-inch floured biscuit cutter, press the cutter straight down into the dough, without turning.
Transfer biscuits to a parchment paper-lined sheet pan.
Gather the dough scraps and form into a ball, then roll out. Cut out 3 more biscuits, 12 total.
Refrigerate the biscuits on a sheet pan for 10 to 30 minutes before baking.
Transfer the biscuits to a new parchment paper-lined sheet pan, spaced 1-inch apart.
Melt 2 tablespoons butter, brush on top of each biscuit.
Bake the biscuits until lightly golden brown on tops and bottoms, about 14 to 18 minutes.
Transfer biscuits to a cooling rack while making the gravy.
Gravy
In a small bowl mix together flour, salt, garlic powder, onion powder, and black pepper.
Heat a large nonstick pan over medium heat. Add pork and break up the meat using a wooden spoon. Cook the pork until no longer pink and lightly browned, about 5 minutes.
Melt the butter in the pan. Sprinkle the flour mixture over the sausage, stir and cook until the flour is absorbed, 1 to 2 minutes.
Slowly whisk in the milk and cream, then turn up the heat to medium-high to bring to a boil.
Reduce heat to a rapid simmer, cook and stir occasionally until the sauce is thickened and can coat the back of a spoon, about 5 minutes.
Taste the gravy and season with salt and pepper as desired.
Split the biscuits in half and serve sausage gravy on top.