In a bowl, mix warm water, sugar, and yeast. Let it sit for 5–10 minutes until foamy.
In a large mixing bowl, combine flour, salt, rosemary, and Parmesan cheese.
Add the yeast mixture and melted butter. Mix until a dough forms.
Knead for 5–7 minutes until smooth and elastic.
Place the dough in a greased bowl, cover, and let it rise in a warm place for about 1 hour or until doubled in size.
Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
Punch down the dough and divide it into 8 equal portions.
Roll each piece into a rope, flatten it slightly, and place some shredded mozzarella in the center.
Pinch the edges tightly to seal the cheese inside and form a pretzel shape.
Bring a large pot of water to a boil and add 1 tbsp baking soda.
Boil each pretzel for 20–30 seconds, then transfer to the prepared baking sheet.
Brush each pretzel with beaten egg.
Sprinkle extra Parmesan and rosemary on top.
Bake for 12–15 minutes or until golden brown.
Let them cool slightly before enjoying the gooey, cheesy goodness!