Light Brioche Burger Buns

Step 1

In a glass measuring cup, combine first 4 ingredients. Let stand until foamy, about 5 minutes. Meanwhile, beat 1 egg.
In a large bowl, whisk flours with salt. Add butter and rub into flour with your fingers, making crumbs. Using dough scraper, stir in yeast mixture and beaten egg until dough forms. Scrape dough onto well-floured surface and knead until smooth and elastic, about 8-10 minutes. Dough should be slightly tacky.
Shape dough into a ball and place into a greased bowl. Cover and let rise in a warm place until doubled, 1-2 hours.
Line a baking sheet with parchment paper. Divide dough into 8 balls. Gently roll each ball and arrange 2-3 inches apart. Cover and let rise until doubled, 1-2 hours.
Set a large shallow pan of water onto the bottom of the oven. Preheat oven to 400 degrees F, with rack in the center. Beat remaining egg with 1 tbsp water, and brush on top of buns. Sprinkle with sesame seeds if desired. Bake, turning sheet halfway through baking, until tops are golden brown, about 15 minutes. Transfer to wire rack to cool.