In a large bowl, whisk together the warm water and light brown sugar.
Sprinkle over the yeast and set the bowl aside until the yeast is frothy, about 5 minutes.
Next, add the flour and kosher salt. Stir until a shaggy dough forms. If you have a dough whisk, that is great here! If not, use a wooden spoon or your hands - not a regular whisk.
Once the dough forms a rough ball, turn it out onto a lightly floured surface and knead it for 3-4 minutes or until the dough is smooth and elastic. If you poke it gently, it should spring back.
Transfer the dough to a lightly oiled bowl and place it in a warm place to rise until doubled in size, about 90 minutes.
Once the dough has risen, preheat your oven to 400 degrees F.
Turn the dough out onto a lightly floured surface and divide it into 16 pieces.
Roll each piece out into a 6-inch long rope.
Fold the rope into a U shape, cross the ends over each other, and then flip the ends over the bottom of the U to create a classic pretzel shape.
Gently pinch the seams to make the pretzel doesn’t unravel while boiling.
Repeat with the remaining dough pieces.
Bring a large pot of water to a rapid boil and very slowly add the baking soda. Stir until the baking soda is fully dissolved.
Boil the pretzels a few at a time for 30 seconds per side. Make sure not to overcrowd the pan.
Remove the boiled pretzels to a parchment-lined baking sheet.
Beat the egg with a small splash of water (about 1 tablespoon) to form an egg wash.
Brush the top of each pretzel with egg wash and sprinkle it with coarse salt.
Bake for 12-15 minutes, or until the pretzels are golden brown.