Mix the Ingredients: In a large bowl, combine the warm water, active sourdough starter, sugar, melted butter, flour, and salt. Mix until a rough dough forms.
Knead the Dough: Turn the dough out onto a lightly floured surface and knead for about 10 minutes until it becomes smooth and elastic. *Add more flour in Tablespoon increments until you can handle the dough and it’s not sticky.
First Rise (Bulk Fermentation): Place the dough in a lightly greased bowl, cover it with a damp cloth, and let it rise at room temperature for 4-6 hours, or until it has doubled in size.
Shape the Dough: After the first rise, punch down the dough to release any air bubbles. Shape it into a loaf or your desired shape and place it in a greased loaf pan or on a baking sheet.
Preheat the Oven: Preheat your oven to 375°F (190°C).
Second Rise (Final Proof): Cover the shaped dough with a damp cloth and let it rise for another 2-4 hours, or until it has doubled in size again.
Bake: Bake the bread in the pre-heated oven for 30-35 minutes, or until the crust is golden brown and the bread sounds hollow when tapped on the bottom. Oven heat can fluctuate, so some loaves of bread may require up to 60 minutes of baking. Always use a thermometer to ensure the center of the loaf reaches between 195°F and 200°F for perfect doneness.
Cool: Allow the bread to cool on a wire rack before slicing and serving.