Ingredients:

For the levain:

1/5 cup (36g) sourdough starter, recently fed at 100% hydration

2 heaping tablespoons (45g) Organic Edison flour

2 heaping tablespoons (45g) Skagit 1109 flour

½ cup water, room temperature

1 tablespoon (18g) honey

For the final dough:

All of the levain

2.5 cups (540g) Organic Edison flour

½ cups (120g) Skagit 1109 flour

1 1/3 cups (275g) water, room temperature

2/3 cups (160g) milk, room temperature

8 tablespoons (113g) butter, unsalted, cold

2 tablespoons (36g) caster sugar or honey

3 teaspoons (15g) sea salt

For the egg wash:

1 egg

1 tablespoon whole milk

For the post-bake glaze (optional):

¼ cup (50g) water

¼ cup honey or cane sugar

Instructions:

1. Make the levain: Refresh your sourdough starter. If it has been in the refrigerator, take it out, let it "wake up" at room temperature, and feed 1 part flour of your choice plus 1 part water. Use to make levain within 12 hours.
2. In a medium-sized jar or mixing bowl, mix together the ingredients for the levain. Cover with plastic wrap and let ferment overnight at room temperature.
3. Make the final dough: before mixing the dough, cut the cold butter into 1/2-inch cubes. Place the cubes of butter in small bowl and set aside to soften.
4. In a bowl of an electric stand mixer, with a mixer running on low speed, mix all of the main dough ingredients, expect for the butter, until just combined and no dry flour bits remain.
5. Turn the mixer speed up to medium-low and mix for about 3-5 minutes until the dough starts to cling to the hook well-incorporated dough. This whole process should take about 7-8 minutes in total.
6. If the butter has yet not softened enough to be easily incorporated into the dough, warm it in the microwave for a few seconds until it softens: you should be able to push it without much resistance.
7. With a mixer running on low again, incorporate the butter one cube at a time. Do not add the next cube until the previous one is fully incorporated.
8. Continue to mix until the dough is smooth and supple and once again starts to cling to the dough hook. Adding the butter and finishing the mix should take a total of about 5 minutes.
9. Cover the bowl with a tea towel or plastic wrap and let the dough bulk ferment for 30 minutes.
10. After the first 30 minutes, fold the dough: lift from one side and fold to the opposite side. Do this all around like you are wrapping a parcel. Alternatively, you may use a coil fold.
11. Cover the dough and let ferment another 30 minutes.
12. Repeat the folds for a total of 3 times during the first 2 hours of fermentation.
13. Once all the folds are complete, cover the dough and let rest for about 2 hours. If your kitchen is on the cool side, add another 30 minutes to the bulk fermentation time. The total bulk fermentation time will be 4-4.5 hours.
14. After the bulk fermentation, the dough should have risen and be soft and airy to the touch. Because this is a soft enriched dough, uncover and place it in your refrigerator for 15-20 minute to firm it up and make shaping easier.
15. While the dough is chilling, prepare a 9"x13" baking pan by buttering or lining it with parchment paper.
16. Gently coax your dough out of its bowl and onto a lightly floured surface.
17. Using a bench knife or plastic dough scraper, divide the dough into 24 pieces of 60-63g each.
18. Flour your hands and shape each piece into a ball using a cupped hand to develop surface tension. If the dough is sticky and hard to shape, dust the top with a pinch or two of flour. Place the shaped dough balls into the pan in rows of 4.
19. Cover the pan with a tea towel or plastic wrap and allow the dough to proof in a warm place for 2-2.5 hours.
20. When the dough is close to being done with its proofing stage* (see Baker's Notes), preheat the oven to 425°F. Place the baking rack in the middle of the oven.
21. Prepare an egg wash by whisking together an egg and a tablespoon of whole milk.
22. Using a pastry brush, gently apply a thin uniform layer of egg wash over the proofed dough.
23. Carefully slide the pan into the oven and bake at 425°F for 25 minutes.
24. Once the 25 minutes are up, turn the oven temperature down to 375°F and bake for an additional 10-15 minutes, until the rolls are golden-brown. Their internal temperature should measure above 200F (93C)** (see Baker's Notes).
25. Let cool in the pan for 5 minutes, then transfer on to a wire cooling rack and let cool for 45 minutes before serving.
26. Optional: while the rolls are cooling, for an extra pop of sweetness bring ¼ cup of water to a boil and stir in ¼ cup of honey or cane sugar. Simmer for 2 minutes and then remove from the heat.
27. Let cool at room temperature for 3-5 minutes and paint a thin layer of this simple syrup on top of the rolls using a pastry brush.