Cemitas (Mexican Sesame Seed Sandwich Buns)

"These cemitas are buttery and sweet with a tender but supportive structure. [Photographs: J. Kenji Lopez-Alt] The cemita, a brioche-like bun from Puebla, may well be the ultimate sandwich of hamburger bun. It has a sweet and savory flavor with a dense-yet-light crumb that can stand up to stacks and stacks of toppings without disintegrating or losing its tenderness. Rich and buttery Mexican sandwich rolls. Why This Recipe Works * Using heavy cream in place of traditional milk and lard, oil, or butter means one fewer ingredient and a richer, more tender texture. * A good amount of sugar makes for a lightly sweet bun that still works perfectly in savory sandwich applications. * An egg wash followed by a sprinkle of sesame seeds and coarse sea salt gives these buns a glossy crust with a big burst of flavor...."