Preheat your oven to 175 degrees Celsius/ 347 degrees Fahrenheit. Line an 8x8 pan with parchment paper.
In a skillet, heat the olive oil and sauté the spring onions and spinach for 2 minutes or long enough for it to wilt slightly. Turn off heat and set aside. If using frozen spinach, just sauté the spring onions and add the thawed spinach directly into the egg mixture.
In a bowl, whisk together the eggs, cream and cheddar cheese, and season with salt and pepper. Then stir in the spinach and spring onions. Pour the egg mixture into the baking tray. Sprinkle over the sweet peas and crumble the feta cheese on top.
Bake for about 25 minutes or until the top is bubbly and eggs are cooked. Let it cool for a few minutes before cutting into squares. You can serve with some toast and avocado.
To store, transfer to an airtight container and store in the fridge for up to 4 days, or in the freezer for up to a month.
Notes
Other add-ons: mushrooms, red bell pepper, ham, baconStorage: Cut into squares and freeze in a single layer on a lined baking sheet. Once frozen, transfer to an airtight container or freezer bags. Reheat in the oven and don't refreeze.