Prepare the Dough:

1. In a large bowl, mix the warm water, sugar, and yeast. Let it sit for 5 minutes until frothy.
2. Add the flour, salt, and melted butter to the yeast mixture. Mix until a dough forms.
3. Knead the dough on a floured surface for 5–7 minutes until smooth and elastic.

Let the Dough Rise:
4. Cover the dough with a damp cloth and let it rise in a warm place for about 1 hour or until it doubles in size.

Shape the Pretzels:
5. Preheat your oven to 425°F (220°C).
6. Punch down the risen dough and divide it into 8 equal portions.
7. Roll each portion into a 12-inch rope. Place a small amount of shredded mozzarella cheese along the center of each rope. Fold the dough over the cheese and pinch to seal.
8. Shape the dough into a pretzel shape.

Boil the Pretzels:
9. In a large pot, bring 10 cups of water to a boil. Add the baking soda.
10. Carefully lower the pretzels into the boiling water, cooking for 1–2 minutes per side.
11. Remove the pretzels with a slotted spoon and place them on a parchment-lined baking sheet.

Add Toppings:
12. Brush each pretzel with an egg wash made from 1 beaten egg.
13. Sprinkle with chopped rosemary, grated Parmesan cheese, and coarse salt.

Bake:
14. Bake in the preheated oven for 12–15 minutes or until golden brown.

Serve:
15. Allow the pretzels to cool slightly before serving. Enjoy the melty mozzarella center and flavorful toppings!