In a small bowl, combine warm water with instant yeast and sugar. Stir gently and let sit for 5 minutes until foamy.

In a large mixing bowl, whisk together all-purpose flour and salt. Make a well and pour in the activated yeast mixture. Mix until shaggy dough forms.

Transfer the dough onto a floured surface and knead for about 8 minutes until smooth and elastic. Incorporate fresh rosemary and Parmesan cheese.

Place the kneaded dough in a greased bowl, cover, and let it rise until doubled in size, about 1 hour.

Preheat the oven to 425°F (220°C) and line a large baking sheet with parchment paper.

Punch down the risen dough and divide into 8 pieces. Flatten, place mozzarella in the center, seal, and shape into pretzels.

In a pot, bring water to boil and add baking soda. Boil each pretzel for 30 seconds on each side, then transfer to paper towels.

Brush each pretzel with melted butter and sprinkle with sea salt. Bake for 12-15 minutes until golden brown.