Put the Unsalted Butter (2 tablespoon) in a large and high pan and place it over medium heat. Let it melt and then add Garlic (3 clove) and Onion (1). Cook for 5 minutes until the onions start to soften. Stir regularly.
In the meantime, remove the core of the Red Cabbage (2 pound) and chop up the leaves. Peel the Potato (1) and cut it into small chunks.
Add the chopped red cabbage and potato to the soft onion in the pan. Season generously with Ground Black Pepper (to taste) and Salt (to taste). Stir the vegetables well. Put a lid on the pan and cook for 5 minutes. Stir regularly.
Add the Chicken Stock (4 cup). Put the lid back on the pan and bring the soup to a boil over high heat. Once boiling, turn the heat low and simmer for 10 minutes. It's important that the cabbage stays 'al dente'.
Check regularly to see how soft it is. Remove half of the red cabbage to a bowl when it is still a little crunchy.
Cook the remaining red cabbage in the hot stock for another 3 minutes. Then blend it well using a stick mixer until smooth (or use a blender). Add the red cabbage you kept aside back to the pan and stir well.
Check the seasoning and add extra Ground Black Pepper (to taste) or Salt (to taste). Scoop the cabbage soup into large bowls. Sprinkle with the Blue Cheese (2 tablespoon). Serve hot and enjoy!