Preheat the oven to 170°C (340°F/Gas 3).
Heat a tablespoon of olive oil in a wok and fry the spinach with the water still clinging to it for a few minutes, until cooked. Add the lemon juice, stir and season with salt and pepper. Beat the eggs with the cream, grind in some pepper and salt and fold in the mint. Grease a (preferably square) brownie baking tin or six small tins with 2 tablespoons of olive oil and cut a sheet of baking paper to the fit the bottom. Grease. Spread the spinach on the bottom of the tin and cover with the egg mixture. Shake the tin slightly in order for the egg to even out and blend with the spinach. Generously sprinkle with pecorino and reserve a little to garnish. Place the frittata in the middle of the hot oven for approx. 15 minutes. It is ready when the top starts turning light brown and feels firm. Leave to cool and cut in diamond or block shapes. Garnish with the reserved pecorino. Serve with a small green salad.