Challah (Braided Egg Bread)

Stir together milk, 1 tsp. sugar, and yeast in a large bowl; let sit until foamy, 10 minutes. Meanwhile, in a small bowl, whisk together butter and eggs. Add to yeast mixture and stir to combine. Add flour, remaining sugar, and salt and stir with a wooden spoon until a dough forms. Transfer dough to a lightly floured work surface and knead until smooth, 6–8 minutes. Transfer to a lightly greased large bowl and cover with plastic wrap; let sit until doubled in size, about 1 hour. Uncover, punch dough down, and re-cover; let sit until slightly puffed, 30 minutes.

Uncover dough, divide into 4 equal portions, and roll each into a 16"-long rope. Align dough ropes side by side, perpendicular to you, and pinch together ends farthest from you to form one end of loaf. Braid ropes and pinch ends together to seal. Transfer braided loaf to a parchment paper—lined baking sheet and cover loosely with plastic wrap; let proof for 1 hour.

Heat oven to 375°. Stir together egg yolk and 1 tbsp. water in a small bowl and brush all over surface of loaf; sprinkle evenly with sesame seeds. Bake until loaf is dark golden brown, 30–35 minutes. Transfer to a wire rack and let cool for 30 minutes before serving.