Preheat oven to 180°C (fan). Grease your pie dish lightly.
Sauté the filling: Heat olive oil in a large pan. Sauté onion and garlic until soft. Add spinach and cook until wilted.
Stir in tomato paste, olives, capers, and seasonings. Add chopped lampuki and cook gently for 5–7 minutes until just opaque. Remove from heat and let cool.
Roll out half the pastry and line the base of the pie dish.
Fill the pie with the lampuki mixture, then cover with the top layer of pastry. Seal the edges and cut a small vent in the center.
Brush the top with beaten egg.
Bake for 40–45 minutes or until the pastry is golden brown and cooked through.
Let rest for 10 minutes before serving. Serve warm or at room temperature.