Make the dough: In a large bowl combine All-Purpose Flour and Salt. In a measuring cup dissolve Instant Yeast and Granulated Sugar in lukewarm Water, let sit 5 minutes until foamy, then stir in Olive Oil. Pour the wet mixture into the flour and mix until a shaggy dough forms.
Knead the dough on a lightly floured surface for 8–10 minutes until smooth and elastic, or 5–6 minutes in a stand mixer with a dough hook. Form into a ball, coat lightly with oil, place in a bowl, cover, and let rise at room temperature until roughly doubled, about 1 hour.
Prepare the meat topping: Finely chop or pulse in a food processor Tomato, Onion, Green Bell Pepper, Parsley and Garlic until very small. Transfer to a bowl and add the Ground Lamb and Ground Beef.
Season the meat mixture with Tomato Paste, Turkish Red Pepper Paste, Ground Cumin, Sweet Paprika, Aleppo Pepper, Fine Salt and Black Pepper. Mix thoroughly until the mixture becomes a cohesive, slightly pasty spread — taste and adjust seasoning.
Preheat your oven to 245°C (475°F) with a baking stone or heavy baking sheet inside so it gets very hot (at least 30 minutes).
Divide the risen dough into 8–10 equal pieces and shape each into a smooth ball. On a lightly floured surface, roll each ball into a very thin round (about 25–30 cm / 10–12 inches).
Spread a thin, even layer of the meat mixture over each dough round, leaving a small edge free of topping. The thinner the layer, the crispier and more authentic the result.
Bake the lahmacun on the preheated stone or tray for 6–9 minutes, until the edges are crisp and the topping has browned and set. Work in batches if needed.
Make the garnish: Thinly slice Red Onion and toss with the juice of Lemon, a pinch of Sumac and a little chopped parsley (already used in the topping).
To serve, top each hot lahmacun with a handful of fresh parsley and the lemony red onion mixture, fold or roll, and enjoy immediately while warm and crisp.
