Sift the whole wheat flour into a large bowl, add the salt, and mix.

Dissolve the sourdough starter in warm water until fully incorporated. Pour this mixture over the flour.

Knead the dough until sticky but cohesive. Cover and let rest for 30 minutes.

Knead again and perform stretch-and-folds (3-4 times).

Cover the dough with plastic wrap and let it proof at room temperature for 8-12 hours (overnight).

Transfer the dough to a parchment-lined tray, shape it, and let it proof for another 30 minutes.

Bake in a preheated oven at 220°C (430°F) for 40 minutes until the crust is crispy.

Let cool completely before slicing and serving.