35 grams (3/4 c + 2 tbsp) sun-dried tomatoes
105 grams (1/4 c + 3 tbsp) warm water
STARTER
50 grams (1/4 c + 2 tbsp) buckwheat flour
0.2 gram (pinch) instant yeast
65 grams (1/4 c + 1 tsp) water at about 60°F (15°C)
DOUGH
210 grams (11/2 c) white flour, plus additional as needed for working with the dough
40 grams (1/4 c + 1 tbsp) medium whole wheat flour
7 grams (11/8 tsp) fine sea salt
0.2 gram (pinch) instant yeast
85 grams (1/4 c + 11/2 tbsp) cold whole milk
25 grams (13/4 tbsp) unsalted butter, at room temperature
Dusting Mixture, for the linen liner and shaped rolls
FOR THE SUN-DRIED TOMATO WATER
1 Put the sun-dried tomatoes in a medium heatproof storage container. Pour in the water, cover, and let sit at room temperature for 8 to 12 hours.
FOR THE STARTER
1 Put the flour in a medium storage container. Sprinkle the yeast into the water, stir to mix, and pour over the flour. Mix with your fingers, pressing the mixture into the sides, bottom, and corners until all of the flour is wet and fully incorporated. Cover the container and let sit at room temperature for 12 to 16 hours. The starter will be at its peak at around 14 hours.
FOR THE DOUGH
1 Transfer the tomatoes and their soaking water to a blender, preferably a high-powered one, and process until the texture is similar to thin marinara sauce.
2 Stir together the white and whole wheat flours, salt, and yeast in a small bowl.
3 Pour about one-third of the milk around the edges of the starter to release it from the sides of the container. Transfer the starter and milk to an extra-large bowl along with the remaining milk and the sun-dried tomato water. Using a wooden spoon, break the starter up to distribute it in the liquid.
4 Add the flour mixture, reserving about one-sixth of it along the edge of the bowl (see Mixing). Continue to mix with the spoon until most of the dry ingredients have been combined with the starter mixture. Switch to a plastic bowl scraper and continue to mix until incorporated. At this point the dough will be slightly sticky but silky to the touch.
5 Push the dough to one side of the bowl. Roll and tuck the dough (see Rolling and Tucking), adding the reserved flour mixture and a small amount of additional flour to the bowl and your hands as needed. Continue rolling and tucking until the dough feels stronger and begins to resist any further rolling, about 10 times. Then, with cupped hands, tuck the sides under toward the center. Place the dough, seam-side down, in a clean bowl, cover the top of the bowl with a clean kitchen towel, and let rest at room temperature for 45 minutes.
6 For the first stretch and fold (see Stretching and Folding), lightly dust the work surface and your hands with flour. Using the plastic bowl scraper, release the dough from the bowl and set it, seam-side down, on the work surface. Gently stretch it into a roughly rectangular shape. Fold the dough in thirds from top to bottom and then from left to right. With cupped hands, tuck the sides under toward the center. Place the dough in the bowl, seam-side down, cover the bowl with the towel, and let rest for 45 minutes.
7 For the second stretch and fold, repeat the steps for the first stretch and fold, then return the dough to the bowl, cover with the towel, and let rest for 30 minutes.
8 For the third stretch and fold, gently stretch the dough into a rectangle. Pinch the butter into pieces, distributing them over the top of the dough. Using your fingers or a spatula, spread the butter across the surface of the dough. (For photos of the following process, see Incorporating Add-Ins.) Roll up the dough tightly from the end closest to you; at the end of the roll the dough will be seam-side down. Turn it over, seam-side up, and gently press on the seam to flatten the dough slightly. Fold in thirds from left to right and then do 4 or 5 roll and tuck sequences to incorporate the butter. Turn the dough seam-side down and tuck the sides under toward the center. Return the dough to the bowl, cover with the towel, and let rest for 30 minutes.
9 For the fourth and final stretch and fold, repeat the steps for the first stretch and fold, then return the dough to the bowl, cover with the towel, and let rest for 20 minutes.
10 Line a half sheet pan with a linen liner and dust fairly generously with the dusting mixture.
11 Lightly dust the work surface and your hands with flour. Using a bench scraper, divide the dough into 12 equal pieces (about 65 grams each). Let rest for 5 minutes.
12 Tightly roll up the pieces into small tubes about 3 inches (8 cm) long. Let rest for 5 minutes. (For photos of the following process, see Shaping Small Baguettes.) Gently roll each tube until it is about 6 inches (15 cm) long, using a bit more pressure on the ends to taper them. Arrange the baguettes on the lined pan, placing them across the width in one row, and dust well with the dusting mixture. Fold the linen to create support walls along the lengths of the rolls on both sides of each. Fold any extra length of the linen liner over the top or cover with a kitchen towel. Transfer the pan to the refrigerator and chill for 16 to 22 hours.
13 Set up the oven with a cast-iron skillet for steam (see Baking Stones and Steam, then preheat the oven to 480°F (250°C). Line two half sheet pans with silicone baking mats or parchment paper.
14 These rolls will be baked in batches. Using the linen liner, lift and ease each of the rolls off the pan and onto your hand. Set six of them on each of the sheet pans lined with a silicone mat, with the length of the rolls running across the pan. Score the top of each roll with a single, straight score or a triple slash on the diagonal (see Scoring).
15 Put one pan of rolls in the oven. Using heavy- duty oven mitts or potholders, pull out the hot skillet, add about 11/2 cups of ice cubes, then slide it back in and close the oven door. Immediately lower the oven temperature to 440°F (225°C) and bake, rotating the pan about two-thirds of the way through baking, until the tops are a light golden brown (best seen along the edges where the roll was scored), 12 to 16 minutes.
16 Set the first pan of rolls on a cooling rack. Carefully pull out the skillet and pour out any remaining water. Set the skillet back on the rack and allow the oven temperature to return to 480°F (250°C). Then bake the second pan of rolls in the same way, once again adding about 11/2 cups of ice cubes to the skillet to create steam.
17 With both batches, give the rolls a few minutes to cool slightly, then place them directly on the cooling rack and let cool completely, about 1 hour. The rolls are best eaten the day they’re baked, but once completely cooled they can be stored (uncut) in a paper bag or cardboard box for up to 24 hours.