Preheat the oven to 200 degrees top and bottom heat.
Peel and finely chop onions and garlic. Peel the potatoes and cut into 2 cm cubes, halve the Brussels sprouts.
Heat 2 tablespoons of oil in a large saucepan. Add the vegetables, sweat for 2 - 3 minutes and deglaze with hot vegetable stock. Let cook for 10-15 minutes. Add sour cream and nutmeg and puree everything in the pot. Season with salt and pepper.
Bake the baguette on a tray in the middle of the oven for 8 minutes.
Fry the bacon without fat in a small pan for 5 minutes until crispy.
Cut the baguette into slices, pour the Brussels sprouts soup into bowls and serve sprinkled with the bacon.