The day before you want to make the bread, prepare the dough. In the bowl of a stand mixer fitted with the dough hook attachment, mix the bread flour, dry milk, sugar, and salt on low speed to combine, about 30 seconds - 1 minute. Add the yeast and mix to combine, about 30 seconds more.

Add the milk and eggs and mix on low speed until it begins to come together to form a shaggy dough, 3 minutes. Scrape the base and sides of the bowl well, then raise the speed to medium and mix for 4 minutes more, until the dough is fairly smooth.

With the mixer running on medium speed, begin to add the butter a few pieces at a time, allowing each addition to incorporate almost completely before adding the next. Continue this process until all of the butter is added, this will take 7-8 minutes of additional mixing time. About halfway through the process, stop the mixer and scrape the base and sides of the bowl well before continuing to mix.

Continue to mix the dough on medium speed until totally smooth, 2 minutes more. Transfer the dough to a large greased bowl, and cover with plastic wrap.

Let the dough rise at room temperature until visibly puffy, 45 minutes - 1 hour 15 minutes.

Uncover the dough, and sprinkle about ⅓ of the chocolate chips into the bowl. Use a bowl scraper to reach under the dough inside the bowl and fold it up and over onto itself. Repeat this process 6 times. Repeat this process, sprinkling another ⅓ of the chocolate chips into the bowl, and repeating the folding process.

When all the chocolate has been incorporated, cover the bowl and transfer it to the refrigerator to rise for at least 10 hours (overnight), and up to 24 hours.

The next day, remove the dough from the refrigerator. Divide it into 12 even pieces (about 120 g each). Roughly form each piece into a round, and place on a lightly floured work surface. Cover with greased plastic wrap or a clean kitchen towel and let rise for 20 minutes.

Line two baking sheets with parchment paper. Working with one piece of dough at a time, on a lightly floured work surface, press the dough all over with your fingertips to flatten it. Starting with the part of dough farthest away from you, fold the dough over onto itself, using your fingertips to press it down firmly as you go. Repeat this process 2 or 3 more times—as you work, the piece of dough will become slightly longer.

When there’s about ½ inch / 1 cm of dough left that hasn’t been folded, switch from your fingertips to the heel of your hand to secure the dough as you fold it over, finally forming the dough into a rough log.

Starting in the center of each log, roll it under your fingers and upper portion of your palms into a baguette shape about 6 inch / 15 cm long, applying slightly more pressure to the ends of the dough to taper them slightly.

Gently transfer the miniature loaves to the prepared baking sheets, then repeat steps 9-11 until you’ve shaped all of the pieces of dough. Evenly divide the rolls between baking sheets, placing 6 rolls on each baking sheet.

Use a lame or very sharp knife to score each loaf. This may seem unusual if you bake a lot of bread - but it’s very hard to score enriched doughs when they are soft, warm and puffy. Scoring them immediately after shaping makes it easy! Make 5-7 short diagonal cuts across the surface of each piece of dough.

Loosely cover the loaves with greased plastic wrap or clean dish towels and let rise until puffy and double in size, 1 hour 30 minutes - 2 hours 30 minutes (it will take less time in a warmer environment, longer time in a cooler one). If a pastry is pressed gently with your fingertip, it should make an indentation, but then the dough should begin to slowly bounce back to the original position.

Towards the end of rise time, preheat the oven to 400°F / 205°C with oven racks in the upper and lower thirds of the oven.

Uncover the mini loaves, and brush the surface of each with egg wash, and transfer to the oven. Immediately reduce the oven temperature to 350°F / 175°C.

Bake the pastries until the exterior is deeply golden brown and the pastry has an internal temperature of at least 195°F / 95°C, 12-15 minutes. Halfway through baking time, rotate the trays front to back, and between oven racks for more even baking.

Gently remove the pastries to a wire rack to cool. Cool at least 10 minutes before serving warm, or cool completely and serve at room temperature.