1. Crumble the yeast into a large mixing bowl. Warm the milk to 98°F (37°C) and pour it over the yeast, mixing until the yeast is fully dissolved. Next, add the softened butter in small pieces.

2. Combine the sugar, salt, and most of the flour, then mix well.

3. Knead the dough thoroughly using a stand mixer or a wooden spoon for 10 minutes. Cover the bowl and let it rise in a warm place for 45 minutes.

4. Turn the dough out onto a floured surface and roll it out to a length. Divide it into 18 equal pieces and shape each one into a ball.

5. Place the balls onto baking sheets lined with parchment paper, leaving space between each bun to allow for even rising. Cover them and let them rise for 1 hour.

6. Preheat your oven to 425°F (220°C) for conventional or 400°F (200°C) for convection.

7. Gently brush the tops of the buns with beaten egg and sprinkle with sesame seeds. Bake the buns in the middle of the oven for about 10 minutes, or until they're golden brown.