Place the grated zucchini, peas, mint, garlic, feta, grated cheese, and the egg yolk in a large bowl and mix well to combine. Sift on the flour and baking powder and stir well. Season well with salt and pepper.
Whisk the egg white until soft peaks form, and then fold gently into the zucchini mixture.
Heat the oil in a large frypan over a medium heat. Add spoonfuls of the batter and fry gently until you see bubbles bursting through the middle of the mixture and the underside is golden. Flip gently and fry the other side until golden. Do this carefully because this is quite a soft mix. Drain the fritters on paper towels and serve warm.
Notes
The trick with these fritters is to avoid overcooking the zucchini. Cook them until just golden. This is a soft batter anyway and if you leave them too long in the pan the zucchini will overcook and become mushy, causing the fritters to collapse a bit. They'll still taste delicious though!
Recipe by The Fare Sage at https://www.thefaresage.com/zucchini-pea-and-mint-fritters/