• Prep. In one bowl, whisk together bread flour, salt, and instant yeast. In another, whisk together water, egg yolk, honey, and olive oil.
• Mix. Make a well in the center of the dry ingredients. Pour the wet ingredients into the center and use a fork to whisk well, gradually incorporating more flour from the sides of the bowl until a thick paste forms. Switch to your hands, a bowl scraper, or spatula and fold the dough over itself, rotating the bowl as you go until all the flour is incorporated and you have a fairly dry but cohesive mass of dough in the bowl.
• Knead. Turn the dough out onto a clean countertop and knead for 2-3 minutes (set a timer!) dusting in flour lightly only if needed. The dough should feel slightly tacky to the touch but not sticky.
• Rise. Shape the dough into a ball, coat lightly with olive oil, and place back in the mixing bowl. Cover the bowl and rest in a warm spot for 1-2 hours. The dough will not double in size; to check if it's ready to shape, press a finger into it. If the indentation fills back in slowly but then stops and remains visible, it's ready. If it fills back in immediately and completely, check again every 15 minutes until it's ready.
• Divide and Pre-Shape. Divide the dough into 3 equal pieces using your kitchen scale (each piece should be about 70 grams). Gently flatten each piece against the counter, stacking any smaller pieces on top of larger ones. Working with one piece at a time, roll the dough into a short, thick log.
• Roll Ropes. Starting with the first log of dough, roll each one into a tapered rope about 11 inches long. Try to keep the "seam" of the dough against the counter so that it seals shut.
• Braid. Join the ends of the three ropes of dough together at one end, pinching to seal. Use the heel of a bench scraper to weigh them down against the counter and hold them in place while you braid. Braid the challah loosely, leaving room for the ropes to expand and fill in during the final rise. Pinch the other end shut, then tuck the joined ends under and place on a parchment lined sheet pan.
• Rise. Lightly spritz the top of the challah with non-stick spray or brush with olive oil, then cover with plastic wrap and let rise in a warm spot for 1 hour. During this rise, the mini challah will double in size and should spring back slightly when you poke it.

During the final 30 minutes of the rise time, preheat the oven to 350°F with a rack in the middle of the oven.

• Egg Wash. In a small bowl whisk together the reserved egg white with a pinch of salt and ¼ teaspoon water. Brush a thin layer of egg wash all over the surface of the mini challah, making sure to get the sides and into the creases.
• Bake. Bake in the center of a 350°F oven for 15 minutes until golden brown all over, though it may still be pale where the ropes intersect. You're looking for an internal temperature of 195°-200°F for doneness.
• Cool. Remove from the oven and let the mini challah cool before slicing or serving.