• In the morning feed your sourdough starter. In a bowl, mix all the starter ingredients until well combined. Scoop the mixture into a clean jar and cover it with a loose lid. Leave it in a warm place to double.
• When the starter has doubled, begin the dough. Add the butter and water in a small saucepan and warm it up until the butter has melted.
• Pour it into a large mixing bowl and add the cold milk. This will bring the temperature of the water down to make it lukewarm.
• Add the sourdough starter and sugar and give it a whisk with a fork to combine it. The starter won't combine properly yet.
• Add the flour and salt and use a fork to combine them. Switch to using your hands and push the dough into a shaggy and sticky dough ball. It won't be smooth yet, but ensure everything is well combined.
• Place the dough ball in a clean, large bowl and give it a stretch and fold. Cover the bowl with a damp tea towel or plastic wrap and place it in a warm place. Over the next hour, give the dough another 3 sets of stretch and folds, spaced around 20 minutes apart.
• After the hour, let the dough rise in the warm spot for another 3-4 hours, ideally around 77°F/25°C) until puffed out by around 40%. If you have a cold kitchen, create a warm and humid spot by placing the dough into a turned-off oven alongside a bowl of boiled water. Replace the water as needed when it cools down.

Cold Proof

• Once risen, cover the bowl and place it in the fridge overnight or for up to 2 days.

Shaping

• Take the cold dough from the refrigerator and pull it from the bowl onto a lightly floured surface. Shape the dough into a smooth ball and let it sit at room temperature for around 10 minutes to relax.
• Use a rolling pin or your fingers to push the dough into a 2cm (just under 1 inch) round. Take a piece of parchment paper and generously dust it with semolina flour.
• Cut out dough circles and place them on the parchment paper With a glass or biscuit cutter that measures around 7.6 cm/3 inches in diameter. Sprinkle the top of the dough circles with more semolina flour.
• Any scraps of dough can be gathered up and rolled again. Let the dough rest and relax first before rolling it out so it doesn't spring back too much.
• Let the dough rounds sit at room temperature for around an hour to puff. At the end of the rising time, preheat a cast iron pan or nonstick skillet over low-medium heat.
• Cooking
• Place 4 muffins in the pan and cook on one side for 6-7 minutes. If your pan has a lid, add this on and it will shorten the time to around 5 minutes.
• Flip the muffins and cook for 5-6 minutes on the other side. You may need to play around with the temperature of your stovetop to get it right. If medium-low is too hot, turn it down to low heat. It should be hot enough to create a deep golden brown toasted exterior but not too hot to burn. If you have a thermometer, the internal temperatures of the muffins should read 200°F/94°C.
• Place the cooked muffins on a wire rack to cool while you cook the remaining muffins. Dust away semolina flour from the pan before adding the next batch, or it will burn.