A very green frittata that makes delicious use of fennel fronds. I love the delicate flavour that they impart, and the kale and feta cheese in this frittata is a perfect match. You could use spinach or chard instead of kale, if desired.
In a small ovenproof frying pan, heat olive oil over medium heat. Add the kale and cook until wilted, then add fennel fronds and cook 1 minute more.
Season the beaten eggs with salt and pepper, then pour into the frying pan. Stir briefly, then leave to allow the bottom of the frittata to set. Once you see the bottom setting, take a spatula to the edges of the pan to ensure that the frittata isn't sticking.
When the frittata starts to set around the edges, sprinkle the crumbled feta over the top. Place the pan under the grill for 5 to 10 minutes, until the frittata is fully set and the edges slightly browned. Serve immediately or at room temperature.