In a small bowl, add water and sugar. Stir until most of the sugar is dissolved. Then add yeast packets. Let sit to bloom for about 10 minutes. (should be foamy)
In a large bowl, combine flour, salt and beaten egg. Pour in bloomed yeast. Mix together until a dough forms. Knead for about 5 minutes. Then add half of the softened butter and knead into dough for another 5 minutes. Cover bowl with plastic wrap (or a bowl cover). Place in a warm place (countertop or proofing drawer), to rise for about and hour. It should double in size.
Turn dough out on lightly floured surface and punch out most of the air. Then use bench scrapper (or knife) to portion into 16 equal pieces. Roll each between your palms into round balls. Line out on a parchment paper covered baking sheet. Cover again with plastic wrap (or a clean kitchen towel) and let proof again, until doubled in size.
Preheat oven to 350degF.
Melt remaining butter. Once buns are done proofing, remove plastic wrap and brush each with melted butter. Sprinkle with sesame seeds. Place in oven to bake for 30 minutes (or until golden brown).
Remove from oven and move immediately to a cooling rack. Let cool at least 15 minutes before slicing in half to use to make burgers or sandwiches.