Heat the butter in a saucepan, then dice the onion and sauté in the butter. Peel and chop the carrots and potatoes (the smaller the pieces, the shorter the time it takes to cook) and add them to the onions. Briefly sauté everything and then deglaze with the vegetable stock. Season with a little pepper and curry to taste. Cook the vegetables until they are soft enough to puree. Let the soup cool down briefly and puree everything. Stir in the cream and then season to taste.
A very simple recipe that I cook very often. Often times I will make more than the stated amount and freeze the rest. Even thawed and briefly boiled, the soup tastes delicious!