Peel the potatoes, sweet potatoes and beetroot and cut into thin slices.
Bring the plant-based cream and almond milk to a simmer in a deep pan or large saucepan. Add the garlic, horseradish cream, salt and nutritional yeast. Add the vegetables and simmer on medium heat for 15 minutes with the lid closed.
In the meantime, preheat the oven to 200°C top and bottom heat.
Mix all ingredients for the crumble.
Rub an oven pan with olive oil, pour in the vegetable mixture and smooth it out. Cover with the crumble and bake on medium heat for 20 minutes. Check in between that the crumble doesn't get too dark. Otherwise cover with baking paper and continue baking. At the end of the baking time, use a fork to check whether the vegetable slices are cooked through. Take out of the oven and serve.