In a mixing bowl, combine warm water, yeast, and sugar. Let it sit for about 5 minutes until foamy.

In a separate bowl, whisk together flour and salt. Gradually add the flour mixture to the yeast mixture, stirring until combined.

Knead the dough using a stand mixer with the dough hook for about 5 minutes or knead by hand on a floured surface for about 8 minutes until smooth and elastic.

Incorporate chopped rosemary and grated Parmesan into the dough. Form into a ball, place in a greased bowl, cover with a towel, and let rise for about 1 hour until doubled in size.

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

Punch down risen dough and divide into 8 pieces. Flatten each piece and place a cube of mozzarella in the center. Fold the dough around cheese to seal, forming a ball.

Roll each ball into a rope about 24 inches long, then shape into pretzels on the baking sheet.

In a saucepan, boil 4 cups of water and carefully add baking soda. Drop pretzels into boiling water using a slotted spoon, cooking for about 30 seconds each, then drain on paper towels.

Brush each pretzel with melted butter and sprinkle with coarse sea salt.

Bake in the preheated oven for 12-15 minutes or until golden brown.