Activate the Yeast: In a small bowl, stir the yeast into the warm water until dissolved. Whisk in the olive oil.

Mix the Dough: In a large mixing bowl, whisk together the flour and salt. Pour in the liquid mixture and stir with a wooden spoon until all flour is absorbed and a shaggy dough forms. Cover with plastic wrap or a damp towel and rest for 30 minutes at room temperature.

Stretch & Folds: After resting, wet your hand to prevent sticking. Grab one side of the dough, stretch it upward until it resists, then fold it back over. Rotate the bowl 90° and repeat. Continue 4–6 times until the dough feels tighter. Cover and rest for 30 minutes. Repeat this process three times total (with 30-minute rests in between).

Slap & Fold: Turn the dough out onto a clean counter. With wet hands, lift the dough, slap the bottom half onto the counter, then fold the top half over. Rotate and repeat 3–4 times until the dough tightens into a smooth ball. Place the dough back in the bowl, smooth side up. Cover and refrigerate overnight.

Shape & Proof: Line a baking sheet with parchment. Oil both the tray and the parchment generously. With oiled hands, gently release the dough from the bowl and flip it smooth-side down onto the tray. Fold the top third into the center, then the bottom third, forming a rectangle. Flip seam-side down and gently stretch wider. Cover with another baking sheet or plastic wrap and let rise for 2 hours at room temperature. (After 1 hour, begin preheating the oven to 450°F with a baking steel or stone on the middle rack.)

Dimple & Bake: Drizzle olive oil over the dough. Dimple all over with oiled fingertips. Gently tug the edges outward to thin slightly. Bake on the hot steel or stone for 20–25 minutes, rotating halfway through, until deeply golden and crisp. Cool completely on a wire rack before slicing. Optional: increase oven to 500°F for an extra 3–4 minutes to crisp further, or toast individual slices when assembling sandwiches.

Pistachio Cream: Blend the Pistachios: In a food processor, pulse pistachios until finely ground. Continue blending until the oils release and the mixture clumps together. Stream in Olive Oil: With the processor running, drizzle in olive oil until the texture flows like lava. Finish with Mascarpone: Add mascarpone and blend until smooth and creamy. Transfer to a container and store chilled. Let come to room temperature before using.

Sandwich Assembly: Prepare the Bread: Slice the cooled schiacciata in half horizontally. Brush the cut sides lightly with olive oil. Toast briefly if desired. Layer the Fillings: Spread a thick layer of pistachio cream on the bottom half. Arrange mortadella slices generously on top. Spoon stracciatella over the mortadella. Sprinkle with crushed pistachios for crunch. Finish & Serve: Top with the other half of bread. Press gently, slice into squares or rectangles, and serve immediately.