For the Pretzel Dough:

• 1 ½ cups warm water (110°F to 115°F)
• 1 packet (2 ¼ teaspoons) active dry yeast
• 1 tablespoon granulated sugar
• 4 cups all-purpose flour
• 1 teaspoon salt
• ¼ cup unsalted butter, melted

For the Filling:

• 8 ounces mozzarella cheese, cut into small cubes

For the Baking Soda Bath:

• 10 cups water
• ⅔ cup baking soda

For Topping:

• 1 large egg, beaten (for egg wash)
• Coarse sea salt (for sprinkling)

Instructions

1. Prepare the Dough:
   • In a large bowl, combine warm water, yeast, and sugar. Let it sit for about 5 minutes until it becomes frothy.
   • Add the flour, salt, and melted butter to the yeast mixture. Mix until a dough forms.
   • Knead the dough on a floured surface for about 5-7 minutes until smooth. Place it in a greased bowl, cover with a kitchen towel, and let it rise in a warm place for about 1 hour or until doubled in size.
2. Shape the Pretzels:
   • Preheat your oven to 425°F (220°C).
   • Once the dough has risen, punch it down and divide it into 8 equal pieces.
   • Roll each piece into a long rope (about 24 inches long). Flatten it slightly, place a cube of mozzarella at the center, and fold the dough over to encase the cheese. Pinch the edges to seal.
   • Shape the filled dough into a pretzel shape.
3. Prepare the Baking Soda Bath:
   • In a large pot, bring 10 cups of water to a boil. Carefully add the baking soda (it will bubble up).
   • Boil each pretzel for about 30 seconds, then remove with a slotted spoon and place on a parchment-lined baking sheet.
4. Bake the Pretzels:
   • Brush each pretzel with the beaten egg and sprinkle with coarse sea salt.
   • Bake for 12-15 minutes or until golden brown.
5. Serve:
   • Let the pretzels cool slightly before serving. Enjoy them warm, preferably with mustard or cheese dip!