In a large mixing bowl, combine the active dry yeast and warm water, allowing it to sit for about 5 minutes until frothy. Stir in the warm milk, melted butter, shortening, salt, and sugar until well blended. Gradually add 2 cups of all-purpose flour, mixing vigorously until soft dough forms. Knead in remaining flour until smooth and elastic, about 8-10 minutes.

Transfer the dough to a greased bowl, coating the surface lightly with oil. Cover with a towel and place in a warm area to rise for 1.5 to 2 hours, until doubled in size.

Punch the risen dough down gently. On a floured surface, roll out to ½ inch thickness. Use round cutters to cut muffin shapes and place on a cornmeal-dusted surface. Cover lightly with a towel and let rise for another hour.

Preheat a skillet over medium-high heat and melt 1-2 tablespoons of butter. Place muffins in the skillet, cooking a few at a time for about 6-7 minutes on each side until golden brown. Transfer to a cooling rack.