Mix warm milk, melted butter, sourdough discard, sugar, and yeast in a large mixing bowl and let sit for a few minutes.
Next, add flour and salt and mix with a dough whisk or wooden spoon until a slightly sticky dough forms and all ingredients are thoroughly combined.
Cover and let rise until doubled in size which should take 60-90 minutes.
After dough has doubled in size (or after chilling dough overnight), dump onto floured surface and press or roll out to about a 1-inch thickness.
Cut rounds with a biscuit cutter or drinking glass/jar. Reshape scraps by stacking them, re-rolling, and cutting.
When you have all muffins shaped, place them on a pan lined heavily with cornmeal or semolina flour. Dust both sides well.
Cover the muffins and allow to rise for about an hour until puffy and light.
Preheat an electric skillet to 300 degrees or a heavy skillet over medium-low heat, and place risen muffins in, leaving a bit of space between each one.
Cover and cook for 5 minutes. Flip and cook on second side for another 5 minutes, covered.
Reduce the heat to about 250, flip the muffins a few more times until the internal temp registers 195-200 degrees F.
Remove to cooling rack and allow to cool to room temperature.
