In a large mixing bowl, combine the sourdough discard, warm water, and instant yeast. Stir until well mixed.
Add the all-purpose flour, salt, and sugar to the mixture. Mix until a dough begins to form.
Knead the dough on a floured surface for about 5-7 minutes until it becomes smooth and elastic.
Place the dough in a greased bowl, cover it with a cloth, and let it rise in a warm place for about 1 hour or until it has doubled in size.
Once the dough has risen, punch it down and roll it out into a rectangle on a floured surface.
Brush the melted butter over the dough, then sprinkle the minced garlic, chopped parsley, and shredded mozzarella cheese evenly on top.
Cut the dough into strips and stack them on top of each other, then cut them into squares.
Place the squares in a greased baking dish, allowing them to touch each other slightly.
Cover the dish with a cloth and let the dough rise again for about 30 minutes.
Preheat the oven to 350°F (175°C). Bake the bread for 25-30 minutes or until golden brown.
