Leftover veg frittata

I hate to waste food, my cupboards and freezer are always better stocked than my fridge, as I know the food in there will last.
I do try and use up everything I have though, and tonight that transpired to a sweet potato and a leek.
I had in plenty of eggs, and some cheese (I always have in cheese, I love cheese), so frittata it was.
I used about half a large sweet potato, and a medium leek for this, plus half a mug of defrosted green beans, snipped up with scissors.
The potato and leek were cut into small pieces and chucked in the oven, tossed with a good drizzle of olive oil for 20 minutes.
After that, they were warmed through in a frying pan, with the green beans, and eight beaten eggs were added.
Cook over a very low heat, until it's mostly set, then sprinkle over the cheese, and put under a hot grill until completely set and browned.

This is brilliant served cold, I've half of it wrapped in the fridge for when Niamh comes home from school and says, 'I'm Staaaaaaaaaarrrrrving'!