In a large bowl, stir together warm water, yeast, and sugar. Let it sit for 5–10 minutes until it gets foamy. If it doesn't, your yeast might be a dud—start over.
Add in the flour, salt, and melted butter. Stir until it forms a dough, then knead it by hand or mixer for about 8 minutes until smooth and elastic.
Place the dough in a greased bowl, cover it, and let it rise in a warm spot for about an hour or until doubled.
Preheat your oven to 425°F and line a baking sheet with parchment paper.
Punch down the dough and divide it into 8 equal pieces. Shape each into a tight ball and slightly flatten it.
In a large pot, bring about 10 cups of water to a boil. Slowly add baking soda (it’ll foam like a science fair volcano).
Gently drop each dough ball into the boiling water for 30 seconds, then remove with a slotted spoon and place on the baking sheet.
Brush each with the beaten egg and sprinkle with coarse salt.
Bake for 18–20 minutes until deep golden brown. Let cool before slicing.