Begin by adding your ingredients (all except egg wash ingredients) to your stand mixer. Be sure to save the egg whites for your egg wash.
Once added to your mixing bowl turn your mixer on low speed and mix about 7 minutes. The dough should be pulled away from the side, but slightly sticking to the bottom. It should be stuck on the dough hook.
Prepare a large bowl by throughly greasing. Remove the dough, form into a neat ball and place in the greased bowl. Cover with plastic wrap.
Place the bowl in a warm place, let it rise until doubled. This time frame can vary. It typically takes about 8-10 hours for the dough to double.
After the dough has doubled, gently punch the dough down and divide it into eight pieces. Shape each piece into a ball.
Be sure each ball has a smooth surface. Any imperfections in the dough will become more prominent once it has risen. You can smooth the surface by gently rolling the ball in your hands.
Gently press down each dough ball with the pal of your hand to flatten the dough until it is about 3" across.
Place the unbaked buns on a lightly greased or parchment-lined baking sheet.
Cover with plastic wrap and let rise until noticeably puffy, about 2-3 hours.
Prepare to bake your homemade hamburger buns
Once the buns have risen, preheat the oven to 375°F.
Brush the buns with about half of the melted butter. Vigorously whisk the water and egg whites together. Brush the egg white/water mixture right over the melted butter; it helps the seeds adhere. Sprinkle buns with sesame seeds, or another seed of your choice.
Bake for 15 to 18 minutes, until golden brown on tops. Remove them from the oven and carefully brush with the remaining melted butter; this will give the buns a satiny, buttery crust, but be careful not to brush the seeds off.