Step 1 Preheat oven to 200ºC. Spray a 20cm round cake pan with cooking oil, line base and side with non-stick baking paper. Place tomatoes in the pan. Cook in the oven for 10 minutes, or until slightly collapsed. Reduce oven temperature to 170°C.

Step 2 Meanwhile, whisk together the eggs, egg whites, ricotta, sour cream, oregano and garlic until combined. Pour egg mixture over tomatoes and lightly tap the pan on the bench to evenly spread.

Step 3 Bake for 45 minutes, until the frittata is just set. Remove from the oven and set aside in the pan for 10 minutes. Carefully turn the frittata out onto a chopping board. Cut into wedges and serve with rocket salad.