Add warm water, brown sugar, and yeast to your mixer bowl. Let sit for 5–10 minutes, until the yeast becomes foamy.
Add melted butter, salt, and flour gradually. If using a mixer, knead with a dough hook on low for 5–7 minutes. If kneading by hand, knead for 10 minutes, until the dough is smooth and slightly tacky.
Place the dough in a lightly greased bowl, cover, and let rise for about 1 hour, or until doubled in size.
Punch down the dough and divide into 8 equal pieces. Roll each piece into a rope about 20–25 inches long. Shape each rope into a pretzel and pinch the ends down so they stay in place.
Bring 8 cups of water to a gentle boil, then add ½ cup of baking soda.
Carefully place each pretzel into the baking soda bath for 5–10 seconds. Remove with a slotted spoon and place on a parchment-lined baking sheet.
If using an egg wash, brush each pretzel lightly with beaten egg, then sprinkle with coarse kosher salt.
Bake at 450°F for 15 minutes or until golden brown.
Brush the warm pretzels with melted butter for that soft, buttery finish.
