If using active dry yeast, start by measuring warm water into a liquid measuring cup and sprinkling yeast on top. Set aside for 5-10 minutes. Meanwhile, measure and combine the sugar, butter, egg, and salt in a large mixing bowl or stand mixer. Add the yeast-water mixture, and stir briefly to mix.

If using instant yeast, simply combine water, yeast, sugar, butter, egg, and salt in the large bowl and stir briefly to mix.

Add 3 cups flour. Stir vigorously by hand, or knead with the stand mixer’s dough hook, until the flour is incorporated and the dough has an even texture and forms a smooth ball. If stirring by hand, you’ll probably need to turn the dough out onto a work surface once the flour is mostly incorporated but the dough is still a little lumpy. Knead it by hand for 1-2 minutes until it’s smooth and even. When finished, the dough should be feel tacky but barely stick to your fingers. If it’s too wet and sticky, add up to ¼ cup of additional flour.

Place dough in a lightly greased bowl. Set aside in a warm spot to rise until doubled in size, roughly 1-2 hours.

After the dough has doubled, punch it down and turn it out onto a lightly floured work surface. Using a bench scraper or knife, divide the dough into 8 equal pieces. (Use a kitchen scale if you have one and want to be sure the pieces are very evenly-sized.) Stretch and shape each piece into a round ball, and space them a few inches apart on a baking sheet, lined with parchment or silicone mats if you have them.

Loosely cover the baking sheets with a clean kitchen towel, and set aside once more to rise for about 45 minutes. Toward the end of the rising time, preheat the oven to 400 degrees F.

Once the buns are puffy and the oven is preheated, combine the egg yolk and water or milk in a small bowl to make an egg wash. Lightly brush the egg wash over the top of each bun, and sprinkle with sesame or poppy seeds if desired.

Bake buns for 12-14 minutes. If using more than one baking sheet, check halfway through the baking time and rotate the pans to ensure even browning. Remove buns and let cool on a wire rack until ready to use. Enjoy with your favorite burger or sandwich!