Add the peanut oil to a large Dutch oven fitted with a fry/candy thermometer and place over medium-high heat until the oil reaches 350ºF. Keep an eye on the thermometer so the oil doesn't rise above the target temperature. When it reaches about 300ºF, back off the heat.
Meanwhile, sift the dry ingredients together in a large mixing bowl. Working quickly so the fats don't melt, use your fingertips to rub the butter and lard into the dry mixture until it resembles coarse crumbs.
Make a well in the center of the dry mixture and pour in the buttermilk. Stir until dough just begins to come together. It will be very sticky. While it is still in the bowl, fold the dough over itself 2 to 3 times so that it absorbs any remaining flour, then turn it out onto a lightly floured work surface.
Dust the top of the dough with flour and, with floured hands, gently fold the dough over itself 8 more times, turning one quarter turn between each folding motion. Then, press dough out to a thickness of 1 inch.
Cut out dough using a 2 1/4-inch doughnut cutter or pastry ring, and a 1 1/4-inch ring for the center hole. Make your cuts as close together as possible to limit waste. Re-roll and cut as many doughnuts as possible. Whatever scrap is left should be cut and formed into balls about the same size as the other holes.
Using chopsticks, carefully place the bonuts into the oil, 3 to 4 at a time. Using chopsticks, flip after 1 1/2 to 2 minutes per side and continue cooking. When the cold dough hits the fat, the temperature is going to fall quickly, so boost the heat and keep an eye on the thermometer.
Remove the golden-brown rings-of-wonder to a cooling rack inverted over a paper towel-lined half-sheet pan and cool for 2 minutes before glazing. Finish up frying the holes in 2 batches until golden brown, about 1 to 2 minutes per side.