Sprinkle the yeast into the bowl of a stand mixer and add the warm water. Give it a little swish to distribute then leave it to proof until bubbly and creamy, about 5 to 10 minutes.
Meanwhile, put the buttermilk and the butter, in a small saucepan and heat over medium low, just until the butter melts. Let the mixture cool slightly — you want it just warm enough to touch.
Add the honey, salt, and warm buttermilk mixture to the yeast in the bowl, then add 1½ cups of flour. Use the dough hook on medium speed to blend the ingredients together until you have a wet, shaggy dough. Scrape the sides of the bowl and the hook if necessary. Add more flour, ¼ cup at a time, kneading at medium speed until you have a mass of smooth dough (you may not use all of the flour). Continue kneading until the dough is smooth and elastic and comes together in a nice ball, about 5 minutes.
Gather the dough into a ball and place it in a large, buttered bowl. Cover the bowl with plastic wrap. Let the dough rise until doubled in bulk, about 1½ hours. Here’s a tip I learned from my bread-baking friend Holly. Place the bowl in the microwave. It is a warm, draft-free place. First, create a moist, warm dough habitat by putting a measuring cup with ½ cup of water in the microwave and zap it for 2 minutes, until the inside is nice and steamy. Quickly stick the dough bowl in and shut the door. Just leave a post-it note so no one turns the microwave on.
Punch down the risen dough and form it into a loaf. Transfer it to a buttered 8-by-4-inch loaf pan and leave to rise until it fills the pan, about another hour.
Heat the oven to 375°. Bake the bread until it is nicely browned, about 30 to 35 minutes. Turn the bread out into your oven-mitted hand and tap on the bottom; it should give a nice hollow thud. Remove the bread from the pan and wrap in it in a clean tea towel. Place the bread on a rack until it is completely cool. Makes 1 loaf