Combine 620 grams of the bread flour and the yeast in the bowl of a stand mixer.

Whisk together the reserved 40 grams of bread flour and the water in a 4-cup microwave safe container and microwave for 1 minute. Whisk to smooth and microwave for another 40-60 seconds until mixture reaches 140° F. Whisk to smooth flour paste.

Add sugar and canola oil and whisk to combine. Add ½ cup of the milk and whisk until smooth. Add remaining ½ cup of milk and whisk until smooth. At this point the slurry should be under 115° F.

Add the slurry to the flour and yeast in the bowl of the stand mixer and mix together with a large spoon or spatula until combined and no dry pockets of flour remain. Cover bowl with plastic wrap and let rest for 15 minutes.

Uncover dough and sprinkle salt over the surface of the dough. Knead using the dough hook attachment on low speed for 15 minutes.

Transfer dough to a lightly oiled cutting board and divide into 12 even pieces. (Each piece should weigh around 100 grams.)

Cup hand over each portion of dough and roll it in a circle against the oiled cutting board until it becomes a tight seamless ball.

Transfer the dough balls to a sheet tray that has been lined with plastic wrap and coated with 1 Tbsp of canola oil leaving 2 inches of space between each ball. Lightly spray the tops of the dough balls with non-stick spray and cover the whole tray tightly with plastic wrap. Refrigerate for at least 8 hours or overnight.

When you are ready to cook the muffins, remove the cold dough balls from the refrigerator.

Line two sheet trays with wax or parchment paper and sprinkle evenly with cornmeal.

Place 6 dough balls on each cornmeal lined tray. Press each dough ball down with your fingers until it is about ½ inch thick and 4 inches across. Spray the tops of the flattened muffins with non-stick spray and gently cover with plastic wrap. Let rise for 90 minutes or until doubled in size to 1 inch thick.

Preheat a 12” cast iron skillet to medium low.

Slide a thin spatula under each muffin and use it to transfer the muffin to the preheated pan. Gently slide the muffins off of the spatula and into the pan. Do not flip into pan! Place 2-3 muffins into your ungreased preheated skillet (they should not touch each other), cover and cook for 5 minutes.  Check and rotate the muffins every two minutes to ensure even browning and that they are not burning. If the muffins are browning too quickly, turn down your heat.

Gently flip the muffins, cover and cook for an additional 4 minutes, until the other side is golden brown and they register 200° F on an instant thermometer inserted from the side. The top of the muffin without cornmeal browns much faster than the bottom with cornmeal. Check frequently and rotate to ensure even browning. Turn down your heat if necessary.

Remove cooked muffins from the pan and transfer to a cooling rack to cool. Repeat until all the muffins are cooked.

Cool completely (or don’t—they’re great warm 😋) before splitting with a fork and enjoying!