This tart is so good that my cauliflower hating partner willingly went back for seconds. What I will say is that you cannot skip the step where you roast the cauliflower and you can’t skip blind baking the crust which does make this a kind of tedious recipe for a week night but since this will stay in the fridge for a good four days OR you can freeze the pre-baked or baked tart I would suggest doing this as part of a prep or even being a sneaky genius and making two at a time, eating one and freezing the other for the future.
Cauliflower Tart
Preheat an oven 215°C. On a baking sheet toss the cauliflower with olive oil, salt, and pepper and roast for 30 minutes, flipping halfway. Allow to cool completely.
Reduce the oven temperature to 190°C. Roll out your dough and transfer to a 9" pie tin. Poke several holes in the dough on the bottom then blind bake the crust for 8-10 minutes until it just faintly changes color. Set aside to cool completely.
In a small frying pan, heat a small amount of olive oil and then turn the heat down the low and add the onions, cooking them slowly for 20-30 minutes until they caramelize.
Place the caramelized onions and cauliflower in the pre-baked crust, spreading them out evenly.
In a large bowl combined the eggs, mustard, cream, and seasoning and whisk very well until completely combined. Add the Gruyere then pour the entire mixture over the vegetables in the crust, coating them. Top with parmesan cheese and then bake at 190°C for 35-40 minutes.