Cook the peas according to the instructions on the packet. Cut the spring onions into 3 cm long pieces.
Mix the egg, milk, parmesan, basil strips, salt and pepper together.
Brush the bottom of a hot coated pan (should not be more than 20 cm in diameter) with oil. Fry the peas and spring onions for approx. 1 minute while stirring. Add the egg mixture and cover and let set over low to medium heat.
Place the frittata on a plate, put the other side back into the pan and cook for another 2 minutes.