In a large bowl, combine warm water, yeast, and sugar. Let it sit for 5 minutes, until foamy.
Stir in flour and salt. Mix until dough forms. Knead on a floured surface for 8 minutes until smooth.
Place in a greased bowl, cover, and let rise in a warm spot for 1 hour.
Punch down and divide into 8 pieces. Shape each piece into a tight ball, then flatten slightly to bun shape.
Preheat oven to 425°F. Line a baking sheet with parchment paper.
Bring a large pot of water and baking soda to a boil. Gently boil each bun for 30 seconds per side.
Transfer to baking sheet, brush with egg wash, and sprinkle with coarse salt.
Bake for 13–15 minutes, until deeply golden brown. Cool slightly before slicing.