Melt butter in a pot and add in the red cabbage and onion. Saute over medium heat until vegetables start to soften. Turn the heat down to low and continue to cook until cabbage has decresed in volume by half. Add in flour and cook for another minute.
Add in water, cream, powdered bouillon and salt and simmer for 5 minutes.
Transfer soup into a blender and mix until smooth. Strain through a colander for an even smoother soup.
Divide 200 milliliters of the soup into two separate bowls. Add lemon juice in one and baking soda in the other. Microwave the bowls of soup for 30 seconds at 600 watts.