In a small bowl, mix the yeast with warm water and let it sit for a few minutes until it becomes frothy.

In a large bowl, combine the flour and yeast mixture, mixing until a dough forms. Add the salt and knead on a floured surface for about 10 minutes until smooth and elastic. (You can also use a stand mixer with a dough hook.) Dust with semolina, cover with a damp tea towel, and rest for 30 minutes.

Stretch the dough into a rectangle and fold it into thirds like a letter. Shape it into a ball, place it in an oiled container with a lid, and let it rest at room temperature for 2 hours. Then, refrigerate overnight (or up to 4 days) for a slow prove.

Remove the dough from the fridge 2 hours before use. Preheat the oven to 220°C. Place a 25 cm round baking tray upside-down in the oven to heat.

Divide the dough into two balls. On a floured surface, stretch each ball into a 20–22 cm round. Place one round on baking paper dusted with semolina. Spread half the crushed tomatoes over half of the dough, then layer with mozzarella, artichokes, olives, ham slices, and mushrooms. Season with salt and drizzle with olive oil.

Fold the dough over the filling to create a half-moon shape, pinching the edges to seal. Brush the top with reserved crushed tomatoes and drizzle with olive oil.

Using oven mitts, carefully place the calzone (on baking paper) onto the hot tray. Bake for 30 minutes until puffed and golden.

Remove from the oven, drizzle with olive oil, and serve hot. Repeat with the second dough ball and remaining filling.

Serve the calzones hot with a simple green salad on the side.