To begin, activate the yeast. In a small bowl, mix the warm water with sugar and yeast. Let it sit for 5-10 minutes until frothy, ensuring the yeast is active. Meanwhile, combine the flour and salt in a large mixing bowl.

Gradually add the yeast mixture and olive oil to the flour mixture. Using your hands or a dough hook, knead for 8-10 minutes until a soft, elastic dough forms. If the dough feels sticky, sprinkle a little more flour as needed.

Place the dough in a lightly oiled bowl, cover with a damp cloth, and let it rise in a warm place for 1 hour or until doubled in size. Rising time is essential for a light and airy Pide.

Preheat your oven to 475°F (245°C) and place a baking sheet or pizza stone in the oven to heat. This will create a hot surface for baking the Pide, ensuring a crispy crust.

Once the dough has risen, punch it down to release any air bubbles. Divide the dough into four equal portions, then roll each portion into an oval shape about 1/4 inch thick on a floured surface.

In a medium bowl, combine the feta, mozzarella, spinach, black pepper, and optional red pepper flakes. Spread an even layer of the filling onto each rolled dough oval, leaving a 1-inch border.

Fold the edges of each dough oval over the filling to form a boat shape, pinching the ends to seal. Brush the edges with beaten egg yolk and sprinkle with sesame seeds if desired.

Carefully transfer each Pide onto the preheated baking sheet or pizza stone. Bake for 10-12 minutes or until golden and the cheese is melted and bubbly. Serve immediately with a side of sliced lemon or fresh herbs to enhance the flavour and enjoy the pide warm, savouring each cheesy and savoury bite.