Melt butter in a large heavy-bottomed frying pan.
Add onion, carrot, green beans and potatoes and sauté over low heat, stirring constantly, for about 5 to 7 minutes, until vegetables begin to color.
Add flour to the skillet and sauté, stirring, for one minute, gradually adding the clear soup.
Reduce heat and simmer gently for 15 minutes until potatoes are cooked.
Add diced tofu to skillet and cook for an additional 5 minutes. Season heavily with salt and freshly ground pepper.
To garnish, sprinkle the potato stew with chopped parsley and serve immediately.