If you are using active dry yeast, proof it: put the lukewarm water in a small bowl, then stir in the sugar and sprinkle the yeast on top, then stir in. If you are using instant yeast or fast rising yeast, just put the yeast in a medium bowl.
Add the flour and sugar to the bowl, stir with a fork, then add the water, salt, and yogurt or buttermilk. Stir it all together with a wooden spoon. It will be quite ragged.
Knead it in the bowl, or on the counter, adding in a little flour if need be to get it to be elastic and not sticky. Knead for maybe four or five minutes.
Move the dough to a lightly oiled bowl, cover with waxed paper or a tea towel, put it in a warm place (like in your oven set on warm, or the stovetop) and let it sit for an hour to rise.
Sprinkle a couple of teaspoons of cornmeal on a baking sheet.
After an hour lightly deflate the dough. Then tear it into eight or nine equal sized lumps. (I used a kitchen scale to ensure they were about the same size.) Using your hands, roll each into a ball, then flatten gently to about 3 to 3-1/2 inches in diameter. Set the discs on the baking sheet and let them sit for about 10 minutes or so.
Heat a griddle or skillet to high. I’ve tried this with several types of cooking surfaces—cast iron skillet, nonstick but heavy skillet, griddle. The one I liked the best was the well seasoned cast iron skillet. I still lightly brushed the surface with cooking oil. Sprinkle the surface with a little cornmeal too.
Set the muffins in the pan and reduce the heat to medium/medium slightly low. Let them cook on the first side for four to five minutes —check to make sure it is not too pale and not getting too dark. Turn and cook on the other side for another four minutes or so.
Remove to a plate, and that is it. Let them cool a little, then devour.