Day before you plan to bake: Feed your starter

1. Feed your sourdough starter with a 50/50 mix of flour to water. Let it ferment at warm room temperature for 4-6 hours, or longer if needed. Once it’s ready, you can place it in the refrigerator until the next day.
2. Remove 100 grams and let it warm up to room temperature before incorporating into the dough. Then feed your sourdough again and store it as you normally do.

Day 2: Mix Dough

1. The following instructions are for mixing the dough by hand. The dough is fairly easy to mix by hand; however, feel free to use a stand mixer, if you prefer.
2. Place the flours (all-purpose, white whole wheat, semolina), sugar, and salt in a large mixing bowl. Whisk to combine.
3. Mix in the sourdough until it is thoroughly incorporated throughout the dough. The dough will be sort of mealy at this point.
4. Heat the butter and milk. Add the water to the butter/milk mixture and let it cool before using in the dough.
5. Pour the butter/milk/water mixture over the dough and mix thorough, using a dough whisk or a wooden spoon. At this point, you will have a shaggy dough.
6. Cover the bowl, and let the dough rest for 15 minutes. Wet your fingers and stretch and fold the dough.

Bulk Ferment

1. Form the dough into a ball, and place it back in the bowl. Let it rest, loosely covered, with a damp, clean towel or bees wrap, for 30 minutes.
2. Repeat the 30-minute rest, and stretch and fold two more times, for a total of three folds, if needed (1 ½ hours). You many only need two folds.
3. Cover the bowl and leave it to rise in a warm place for an additional 60-90 minutes, or until doubled. Depending on how warm it is in your kitchen, it may take more or less time.

Shape Loaf

1. Turn the dough out onto a lightly dusted work surface.
2. Shape the dough into a ball. Then, flatten it out into a rectangular. Fold one end in and then the other end over it like a letter. Flip it over and using your hands, shape it into a ball (boule).

Final Proof

1. Carefully place the shaped boule seam side up in a bowl covered with a flour-dusted towel or a lined and flour-dusted banneton. Let it rise for 1-2 hours, then cover or place in a plastic bag, and place in the refrigerator to cold ferment overnight.
2. You can bake the loaf after allowing it to ferment for 2-3 hours, but the overnight rest in the fridge improves the texture and flavor and allows you to bake it the next evening for dinner, should you so desire.

Day 3: Bake Day

1. Preheat your oven to 450 degrees F (230 degrees C) for at least half an hour while the loaf is still in the refrigerator. Place a lidded pot (Dutch oven or domed bread baker) in the oven to preheat.
2. Carefully invert the bread onto a dough sling or piece of baking parchment. Brush the top with water and sprinkle with sesame seeds.
3. Use a knife or bread lame to slice the top of the loaf with a cross shape. (I used a curved blade lame to make the slashes, and they formed nice ears on the crust.
4. Carefully remove the pot from the oven. Lower the loaf (on the parchment) into the pot, cover, and bake for 25-30 minutes.
5. Reduce the temperature to 425 degrees F (220 degrees C). Using heavy oven mitts, carefully remove the lid from the hot baking pot, and let the loaf bake, uncovered for another 10-15 minutes, until the crust is beautiful golden-brown color and the loaf sounds hollow when thumped on the bottom.
6. Using heavy oven mitts, carefully lift the bread out of the pot and allow it to cool on a wire rack 1-2 hours before slicing.