In a mixing bowl, whisk together the Greek yogurt and eggs until smooth. Gradually stir in the water and olive oil, combining until fully blended. In another bowl, mix the all-purpose flour, sea salt, and baking powder. Gradually fold this dry mixture into the wet ingredients until the batter is uniform. Finally, gently fold in the crumbled feta cheese, ensuring it’s evenly distributed.

In a large mixing bowl, massage the chopped fresh spinach with a sprinkle of sea salt for about 5 minutes to reduce its volume and enhance its flavor. Add the diced spring onions, a splash of olive oil, chopped dill, optional spearmint, and any remaining feta. Stir until all ingredients are well combined.

Preheat your oven to 180°C (355°F) and grease a 9 x 13-inch baking pan with olive oil. Pour half of the prepared batter into the base of the pan, spreading it evenly. Layer the spinach and feta filling on top, ensuring it covers the batter well. Finally, pour the remaining batter over the filling, smoothing it out.

Bake for 40–45 minutes or until the top is golden brown and a toothpick inserted into the center comes out clean. Keep an eye on it towards the end to avoid over-baking.

Let the pie cool slightly in the pan for about 10 minutes before cutting into squares to serve warm.