Wash the spinach.

Blend the spinach with the flour and sift.

Dissolve the yeast in two-thirds of the warm water. Start mixing the dough, gradually adding the liquid.

Once you have a rough dough, add the salt dissolved in the remaining water and the olive oil.
Continue kneading until all the liquid is absorbed.

Transfer the dough to your work surface and knead until smooth and uniform.

Do two sets of stretch-and-folds in the bowl, every 30 minutes.

Let rise for about 1 hour, then cover with plastic wrap and refrigerate overnight.

The next morning, let the dough come to room temperature for a couple of hours.

Spread it out in the oiled baking pan.

Cover with plastic wrap and let rise in the oven with the light on until doubled in size.

Dimple the dough with your fingertips.

Bake in a preheated oven at the highest temperature.

Bake on the lower rack for the first 10 minutes, then add the cheeses and continue baking in the center of the oven for another 10 minutes.

Meanwhile:

Wash the zucchini, trim the ends, and slice thinly with a vegetable peeler or mandoline.

Dress the zucchini with a drizzle of olive oil, a pinch of salt, mint leaves, and Tajín. Set aside.

Thinly slice the preserved lemon.

Once baked, spread the pesto over the focaccia and top with the marinated zucchini, three chopped walnuts, a sprinkle of ricotta salata, and preserved lemon to taste (optional).

I can assure you, it's truly delicious!