Preheat the oven to 350°F (180°C) fan-forced.
Blanch the spinach in boiling water for 30 seconds. Drain and squeeze out as much moisture as possible.
In a large bowl, mix the spinach, cooked quinoa, eggs, Parmesan, and spring onions. Season with salt and pepper.
Spoon the mixture into 8 greased or lined muffin tins. Top with crumbled feta.
Bake for 30 minutes, or until set and lightly golden. Serve warm or cold.