To make this vegan gratin first wash and cut the cauliflower in thin slices. Place the slices in a casserole dish. Now cut thin onion rings and spread the rings over the cauliflower. Sprinkle all of your favourite spices (mine is a mexican spice mix) on the cauliflower, garlic powder, nutmeg, salt and pepper.
Now you need to pour fluid into the casserole dish, so that the vegetables can cook and become soft in the oven. You need to place a well fitting lid on the dish so that the vegetables don't dry out. There are two ingredients I use. One is soy milk, and the other important ingredient is a vegan cream. I use one box of this cream. I use Oatly which is made from oats (haver), which has a wonderful taste. It's a little sweet which is the nice finishing touch for the cauliflower and onions. Bake the cauliflower in a hot oven until the vegetables are almost soft. Now take the dish out of the oven. The vegetables should still be lying in the fluid. Give the vegetables a good turn in the juice.
Now place light bread in the food processor and mix to turn the bread into crumbs. Add a nice thick layer of crumbs on the vegetables, and sprinkle a good olive oil generously and extra herbs (optional) over the crumbs. Place the casserole dish back in the oven, this time without the lid. Continue baking the gratin. If the crumbs get too dark before the dish is ready, just press them a little into the fluid. When is the dish ready? The vegetables should be soft, and the fluid will be thick and not too dry. The gratin is nice with grilled young potatoes, a fresh salad and veggie burgers.