Directions:

FEED YOUR SOURDOUGH STARTER
12 hours before you plan to mix the dough, add the ingredients to make ½ cup (100 g) of active sourdough starter to a clean jar. Stir until combined, loosely cover the jar and let the starter rise at room temperature. (The ingredients will create a total of 115 g active starter but, because some of it will stick to the sides of the jar during the transfer, we are making a little more than needed.) The sourdough starter is ready to use when it has doubled in size and there are plenty of bubbles on the surface and sides of the jar.
MAKE THE DOUGH
Add 100g of the active starter and the rest of the ingredients (except corn meal) to a large bowl and use your hands to mix until well combined. Cover and let rest 30-60 minutes. Turn the dough out onto a floured surface and knead the dough by hand for 5 minutes. (A stand mixer with a dough hook attachment can be used on the lowest speed.)
Place the dough back into the bowl, cover and let ferment on the counter at room temperature 8-12 hours. (Room temperature is 65-70°F)
CUT AND COOK
Turn the dough out onto a floured surface, flour the top of the dough and press it out using your fingertips until it is 1" in thickness.
Use a 3" biscuit cutter to cut rounds and place them on a parchment lined baking sheet that's been sprinkled with cornmeal. Sprinkle the tops with cornmeal, cover with a tea towel and allow to rise for 1 hour at room temperature.
Preheat your non-stick skillet over LOW heat. Place 4 muffins into the skillet spaced 2" apart, cover and cook the first side for 4 minutes. Turn the muffins over and cook for an additional 4 minutes. (When done, the center of a muffin should register about 200°F on an instant-read thermometer.)
NOTES
Use the scoop and level technique to measure your flour if you do not have a kitchen scale. To do this, use a spoon to fluff up the flour in the bag. Use a spoon to scoop the flour into a measuring cup until it is heaped on top. Take a butterknife and level off the top. This should give you the most accurate measurement for flour.
If you live in a very warm or humid environment, you may need to make adjustments in the recipe. I recommend reducing the milk by 30g and using granulated sugar instead of honey to help the dough from being too sticky to work with. Add more liquid if the dough is too stiff.
Store at room temperature for up to 5 days in a container or freeze for up to 3 months.