- Beat together the Ricotta and eggs until smooth.
- Combine the parsley leaves, onion, tuna, grated potato, spinach leaves and black pepper in a large bowl and mix well.
- Grease and line a deep 30 x 20 cm baking dish and arrange the tuna mixture in the base of the dish.
- Pour over the Ricotta mixture then place the sliced Mozzarella over the surface of the dish.
- Bake the frittata in the pre-heated oven 180c for 25-30 minutes until the frittata is golden brown and firm to touch.
- Frittata is also delicious made with left over vegetables or bacon in place of tuna.