Pour the buttermilk into a small pot, and warm the buttermilk just so that it is not cold, but is still comfortable to the touch (about 100 F). Alternatively, heat the buttermilk in the microwave for about 2 minutes to reach this temperature. Set aside for now. Add the active dry yeast, water, and honey to the bowl of a stand mixer. Mix and let stand for 5-10 minutes, until the yeast begins to bloom. If there is no activity after 10 minutes, discard and try new yeast.
Add the flour and salt, and mix with a spoon until a dough forms.
Fit the stand mixer with the dough attachment, and turn it on to begin the kneading process. With the stand mixer on, drizzle in the warmed buttermilk.
Add the soft butter, one tablespoon at a time, and continue kneading the dough for 5-7 minutes until it is smooth and elastic.
Cover the bowl with a towel and proof the dough for 1 hour at room temperature. The dough won’t quite double in size, but it should be smooth and springy.
Turn the dough out onto a lightly floured surface, and use your hands to pat it out into a ½” thick rectangle. Use a glass or 2” wide cookie cutter to stamp out the English muffins. Gather the dough scraps and pat it out again to repeat the process, until you have 10 muffins total.
Place the muffins on a baking sheet dusted with cornmeal and rest the muffins at room temperature for 1 more hour. The muffins will puff up.
Preheat a cast iron skillet to medium-low for 5 minutes. Sprinkle additional cornmeal in the pan, and place 4 English muffins in the pan. Cover, turn the heat low, and cook for 6-7 minutes per side, until the bottoms are browned, or the internal temperature reaches 200 F. Repeat with the remaining muffins. Eat on their own, or use for breakfast sandwiches!