Peel the celeriac and cut it into equally sized dices. You will need to get 400 g of clean celery.
In a saucepan sweat oil, garlic, shallot and bay leaf over medium heat. Add a pinch of salt and let it simmer for 2-3 minutes.
Add the celeriac dices and stir for a minute. Pour the vegetable stock and let simmer for about 25-30 minutes or until the celeriac is done.
Meanwhile, prepare the Brussels sprouts. Remove the outer leaves and quarter the sprouts, leaving a piece of their petiole so that the leaves stick together.
Blanch for a couple of minutes in boiling water, then drain and place in cold water. In a coated pan, warm 1 tbsp. of oil and add the garlic. Sweat for a minute and add the quartered Brussels sprouts. Salt and sauté for 2-3 minutes.
Blend the soup with a mixer until you get a smooth and homogenous purée. Add a few spoonfuls of hot stock if you prefer a less thick and creamy consistency. Taste and add salt and pepper to taste.
Serve the hot celeriac cream and decorate it with the Brussels sprouts, drops of extra virgin olive oil, marjoram and sesame seeds.