Preheat your oven to 190 °C (375 °F) and line a baking sheet with parchment paper.

If you prefer extra smooth dough, place cottage cheese in a mini food processor and pulse until creamy.

Combine flour, baking powder, and salt in a large bowl, whisking to evenly distribute the dry ingredients.

Stir in olive oil, pulsed cottage cheese, chopped spinach, and shredded mozzarella until a cohesive dough forms.

Turn the dough out onto a lightly floured surface and shape it into a thick log.

Slice the log into 6 equal portions and shape each into a flattened round flagel with a hole in the center.

Place flagels onto the prepared baking sheet; brush each top with the beaten egg for a glossy finish, if using.

Bake for about 22–25 minutes until the tops are golden brown and the centers are springy to the touch.

Remove from oven and cool slightly on a wire rack before serving to maintain a soft interior.