Preheat the oven to 200°C/400°F/Gas mark 6. Use the oil to grease a small ovenproof dish or the wells of a muffin tin (2 per serve).
Arrange the feta, peas and spring onion in the dish. Whisk the eggs, mixing through the mint and pour into the dish.
Bake for approximately 30-35 minutes until golden on top and just set.
Notes
Store leftovers in an airtight container in the refrigerator for up to 2 days. Reheat or serve cold.
Serve with a crunchy green salad or steamed green vegetables.
Some brands of cheese (including feta) may contain rennet so are not strictly vegetarian. Check the product you buy uses vegetarian ingredients. Brands vary, it is always important to read labels first.