Mix all ingredients together for the base. Gradually add a little warm water until the dough no longer has a crumbly consistency. Then let the dough rest for 10 minutes. Then line a baking pan (ø 20 cm) with it and pull up an approx. 2 cm high rim.
In the meantime, for the filling, briefly bring the frozen broccoli to the boil for 2 minutes in hot salted water and then drain well. Peel and dice the onions. Mix with the broccoli, season with salt and spread everything on the bottom.
Mix the ingredients for the sauce and pour over the broccoli mixture.
Bake the quiche at 200 ° C top / bottom heat in the preheated oven for 30 minutes.