04Shape the dough into a ball and return it to the same bowl. Cover the bowl with plastic wrap and let it rise in a warm spot in your kitchen until it has doubled in size. This took me a little over an hour, but it could take up to 2 hours, depending on how warm your kitchen is.
05Line a baking sheet with parchment paper. Using a very sharp knife (a dough scraper would be ideal but I didn’t have one), divide the dough into 8 equal parts. I found it helpful to cut the dough in half, then quarters, then each quarter in half, like you are cutting a pie. Gently roll each piece into a smooth ball and place on the baking sheet about 2 inches apart. Cover loosely with a piece of plastic wrap or waxed paper that is lightly coated with butter or canola oil. Let your buns rise for about another hour or so, until about double in size. Again, this may take longer in your kitchen, depending on how warm it is.
06Place a large shallow pan (a half sheet pan is ideal, or a jelly roll pan would work too) of water on the oven floor. Make sure the rack is in the center, and preheat your oven to 400 degrees F. Beat the remaining egg with a tablespoon of water and brush it on top of the buns. Sprinkle poppy seeds or sesame seeds on top of the buns if desired. Pop your buns in the oven and bake for about 7 minutes, then turn the sheet and bake for an additional 7 or 8 minutes, until the tops are nice and golden brown. Baking time is about 15 minutes total. Slide the parchment paper with the buns onto a baking rack to cool completely (or serve slightly warm if you want).