In a large bowl, dissolve 1 1/2 teaspoons of sugar and 2 teaspoons of kosher salt in 1 1/2 cups of warm water (100-110°F). Sprinkle 1 package (2 1/4 teaspoons) of active dry yeast over the water and let stand for 5 minutes until foamy.

Add 4 1/2 cups of all-purpose flour to the yeast mixture and stir until a shaggy dough forms. Turn the dough out onto a lightly floured surface and knead for 5-7 minutes until smooth and elastic. Place the dough in a lightly oiled bowl, turn to coat, and cover with plastic wrap. Let rise in a warm place for 1 hour, or until doubled in size.

Preheat oven to 450°F (232°C). Line two baking sheets with parchment paper. In a large, wide pot, bring 10 cups of water and 2/3 cup of baking soda to a rolling boil.

Divide the dough into 8 equal pieces. Roll each piece into a 24-inch rope. Shape each rope into a pretzel by forming a U-shape, crossing the ends over each other, and pressing them onto the bottom of the U. Place the pretzels on the prepared baking sheets.

Carefully drop each pretzel into the boiling water for 30 seconds. Remove with a slotted spoon and return to the baking sheets. Brush the pretzels with 1 large egg, beaten with 1 tablespoon of water, and sprinkle with pretzel salt.

Bake for 12-14 minutes, or until golden brown. Let cool slightly before serving.