Heat the milk in the microwave for around 1 minute, then stir in the water and sugar, making sure that the liquid is warm on your wrist and not hot. If it seems too hot, allow to cool before proceeding.
Add the yeast packet and stir to mix. Allow to rest for 5 minutes until the yeast begins to foam.
Combine the milk mixture with the flour, salt, and melted butter in the bowl of a stand mixer fitted with the hook attachment. Blend until a soft dough forms.
Cover the bowl and allow to rest in a warm location for at least one hour, until the dough has doubled in size.
Punch down the dough and transfer it to a lightly floured surface.
Roll out the dough until it’s around 1/2 inch thick, then use a round cookie cutter to cut out the muffins.
Dust both sides of the muffins with cornmeal, then allow to rest on a baking sheet lined with parchment paper for 30 minutes to rise.
Heat a skillet over medium heat. When the skillet is hot, transfer the muffins to the pan, leaving around 2 inches between each muffin.
Cover the pan with a lid and cook for 5 to 7 minutes, then flip the muffins and cover the pan. Cook for another 3 to 4 minutes.
If the muffins begin to get too crispy in the skillet before they’re cooked through in the center, preheat the oven to 350 degrees and bake for 10 minutes, until cooked through.