Preheat the oven to 180 degrees Celsius.
In a large frying pan, melt half the butter. Add sliced leek and garlic.
Sauté gently until very soft.
Add the spinach and or rocket. Toss in with the leeks until wilted. Drain off excess liquid. Cool.
Mix in the cheeses and chopped parsley. Stir through the cream and beaten eggs.
Season with salt and freshly ground black pepper.
Melt the remaining butter. Grease a 20x30 cm loose bottomed tin or baking dish.
Brush a sheet of filo pastry with melted butter, place another sheet on top and repeat until 6 sheets lay on top of each other. Place in the tart tin letting the pastry overhang the edges.
Spread the spinach and egg mixture on the pastry base. Make 6 indentations in the filling.
Crack the eggs into the indentations and drizzle with extra virgin olive oil.
Sprinkle with fresh oregano leaves and freshly ground black pepper.
Bake for 20-25 minutes until the tart is set and the eggs are just cooked