Focaccia Sandwich with Prosciutto and Mozzarella

In a large bowl, mix the white flour, salt, and sugar. Dissolve the dry yeast in lukewarm water and let it sit for 5 minutes until small bubbles appear on the surface. Pour the yeast mixture over the flour, add a tablespoon of olive oil, and mix until you get a very sticky and soft dough. Cover the bowl with cling film and leave it in the refrigerator for 24 hours. During this time, the dough will double or even triple in volume and will be full of air bubbles.

Prepare a baking tray of approximately 40x30 cm and grease it well with 2 tablespoons of olive oil. Transfer the proofed dough to the tray and spread it with your fingers to the edges, in an even layer. Cover again with cling film and let it proof for another 2-3 hours at room temperature.

Preheat the oven to 220°C. When the focaccia has proofed perfectly, pour the remaining olive oil evenly over it. Grease your fingers with a little oil and gently press into the dough to create those characteristic dimples. Sprinkle a little salt on top and bake in the preheated oven for 25-30 minutes, until golden and crispy. The resulting focaccia should be airy, fluffy on the inside, and crispy on the outside.