In a large bowl, mix together the warm water, sugar, and active dry yeast. Let the mixture rest for about 5 minutes, or until it becomes foamy and frothy.

Add the flour and salt to the activated yeast mixture, kneading by hand or with a dough hook until the dough is smooth and elastic.

Cover the bowl with a clean kitchen towel and allow the dough to rise in a warm spot for 30 to 45 minutes, or until it has doubled in volume.

Preheat your oven to 425°F (220°C) and prepare a baking sheet by lining it with parchment paper.

In a separate small bowl, mix the cubed mozzarella, chopped fresh rosemary, and grated Parmesan cheese to create the filling.

Once the dough has risen, divide it evenly into 8 portions. Roll each portion into a long rope on a lightly floured surface.

Gently flatten each rope, then place a spoonful of the cheese and herb filling along the center.

Carefully fold the dough over the filling and pinch the edges to seal, shaping each into a classic pretzel form.

In a large pot, bring 4 cups of water to a near boil, then remove it from the heat and stir in the baking soda until fully dissolved.

Using a slotted spatula or spoon, lower each pretzel into the baking soda bath for 30 seconds, then place them on the prepared baking sheet.

Top each pretzel with a generous sprinkle of grated Parmesan cheese and garnish with a few fresh rosemary leaves.

Bake the pretzels in the preheated oven for 15 to 20 minutes, or until the tops are golden brown and the cheese is bubbly and crisp.

Let the pretzels cool slightly before serving for the best texture and flavor.