For the spinach soup, peel the shallots and finely dice the garlic. Melt 2 tablespoons of butter in a saucepan and sauté the shallots/garlic cubes until translucent.
Pour in the soup and bring to the boil. Squeeze the defrosted spinach well, chop it coarsely, add it to the soup and let it boil for 3 minutes. Blend everything with a hand blender and season the spinach soup with salt and pepper.