Blanch the broad beans in large saucepan of boiling water for 5–6 minutes until tender. Leave to cool a little, then pop the beans out of their skins.
Blanch the green beans in a saucepan of boiling water for 1–2 minutes, then drain and refresh under cold running water.
Steam the spinach for 1–2 minutes until wilted. Squeeze out any excess liquid.
In a large bowl, beat the eggs with some salt and pepper, then stir in the beans, spinach, parsley and one-half of the Manchego.
Heat the oil in a frying pan and pour in the egg mixture. Turn the heat down to low and cook for 10–12 minutes until cooked underneath. Sprinkle the remaining cheese over the frittata and cook under a preheated medium grill for 2 minutes until golden.
Turn out onto a board and cut into wedges to serve.