1. In a large mixing bowl, combine warm water, sugar, and yeast. Let it sit for 5–7 minutes until foamy. Add flour, salt, and 2 tablespoons softened butter, mixing until a shaggy dough forms. Knead on a floured surface for 8–10 minutes until smooth and elastic. Place in a greased bowl, cover, and let rise until doubled, about 1–1.5 hours.

2. Melt the remaining butter in a small pan, add minced garlic, and cook for 1–2 minutes until fragrant. Stir in thyme and set aside to cool slightly.

3. Punch down the risen dough and roll it into a rectangle. Brush garlic herb butter evenly over the surface, then sprinkle with mozzarella. Roll up tightly from the long edge into a log.

4. Slice the log lengthwise into two long strands, keeping one end intact. Twist strands over each other with cut sides up. Transfer to a greased loaf pan.

5. Cover loosely and let rise for 30–40 minutes until puffy.

6. Preheat oven to 350°F (175°C). Brush top with beaten egg, then bake for 30–35 minutes until golden brown and cooked through. Tent with foil if browning too quickly.

7. Cool in the pan for 10 minutes before transferring to a wire rack. Serve warm.