In a steamer or a pan inset, steam the broccoli and red pepper until they reach the firmer side of ‘al dente’. You can also use a lidded wok over a high heat and ‘steam-fry’ by adding small amounts of water. Drain and set aside to cool.
Mix together the eggs, yoghurt, milk, garlic, salt and pepper until well combined.
Liberally oil an oven-proof dish* with olive oil and arrange the broccoli and red peppers evenly in the dish. Scatter over the feta cheese and spring onions and pour the egg batter over, very gently pushing the contents down into the batter (they’ll pop back up during cooking).
Bake at 160 degs (Fan) or Gas 4 for about 40 mins, or until the quiche has risen and is golden and just set in the centre.
Let cool for a few minutes before slicing and serving. It will keep well (covered) in the refrigerator for 2-3 days.