Casserole from pureed carrot (it may be a "pie" rather than a "casserole" though - my footing in Anglo cooking terms isn't very strong, feel free to edit) is a traditional Finnish recipe.
Essentially, it consists of cooked and pureed carrots, cream, butter, eggs, breadcrumbs, syrup, and salt, baked in the oven for about an hour. Sometimes, some rice is added as well.
You can imagine what the dairy products add to the dish - they emphasize the delicious carrot taste, and make it rich and heavy.
I'm not a hard-core vegan, but I'm curious what vegetable based alternatives could work to replace them. I'm sure olive oil wouldn't: it has too strong a flavour of its own. Other vegetable oils would add the heaviness, but I find there is something unique to what cream and butter do to such a simple dish, something that no oil known to me can.
Are there other ingredients that could work here? Preferably something that is readily available, as opposed to complicated and expensive vegan "xy replacement" products.