In a large bowl, stir together water, milk, olive oil, sugar, and yeast and set aside until slightly foamy, about 5 minutes.

Add flour and salt to the yeast mixture and mix on low speed until a cohesive dough is formed (if the dough is too sticky, you may need to add a few extra spoonfuls of flour). Increase speed to medium and knead until smooth and elastic, about 5 minutes. Transfer dough to a greased bowl, cover, and set aside until doubled, about 1 to 1½ hours.

In a small bowl, whisk together egg yolk and yogurt until smooth. Set aside.

Preheat the oven to 375°F and set aside two parchment lined baking sheets.

Once the dough has doubled, gently divide into two rounds and transfer to the prepared baking sheets. Using lightly oiled hands, press each round out into a large loaf of ½-inch thickness. The loaves will be about 10 to 12-inches in diameter. Allow the loaves to rest for 20 minutes.

Using slightly oiled fingertips, make indentations around the border of the loaves. Next, press parallel lines across the dough, 1–1½ inches apart. Rotate and repeat to form a diamond lattice. Press firmly without tearing.

Brush the tops of the loaves with the prepared eggwash, and sprinkle generously with sesame and nigella seeds.

Bake the Ramazan Pidesi until golden brown, about 25 to 30 minutes.