This is a classic Chinese soup, made with arrowroot as a thickener instead of cornstarch. Arrowroot is gluten-free and lighter than cornstarch or flour. It should thicken the soup when it comes to simmer for a minute. 
Another thickener from the Japanese kitchen is kuzu, called kudzu in the west. This makes a clear light broth and does not complicate flavors on the palate. They are available in natural foods stores, although supermarkets now carry both in natural foods sections. The toasted sesame oil adds the heat, so go sparingly, as a little goes a long way.
This is a delicious quickie recipe. If you would like to add protein, although it is non-traditional, add a sliced, grilled chicken breast at the end, to warm in the soup, or some grilled or broiled shrimp. Made at home, the soup often tastes better than the take-out variety. The small amount of toasted sesame oil should not complicate the swallow, as it is mild.
Serves 4
- 2 tablespoons peanut oil, or canola oil
- 1 pound cremini or shiitake mushrooms, cleaned, stems removed and thinly-sliced
- 2 garlic cloves, finely-minced
- 4 cups vegetable or chicken stock
- 2 tablespoons rice vinegar
- 2 teaspoons toasted sesame oil
- 1 tablespoon lower sodium soy sauce or amino soy sauce
- 2 teaspoons arrowroot powder
- 2 tablespoons water
- 2 thinly sliced scallions, to garnish
- In a medium stock pot, heat oil over medium heat. Add mushrooms and a pinch of salt. Cover the pot and sweat for five minutes, stirring occasionally. Turn heat to medium high, add garlic and sauté, uncovered, for one minute.
- Add stock, bring the mixture up to a simmer. Cook for five minutes.
- Dissolve arrowroot in water in small bowl. Whisk together rice vinegar, toasted sesame oil, soy or amino soy sauce and add to arrowroot bowl. Stir the arrowroot mixture into the soup and simmer for one minute. Soup will thicken but be translucent. Serve with sliced scallions on top.
For the Puree
Allow the soup to cool. Place a cup in a blender or the bowl of a food processor. Pulse a few times if you have added protein. Then blend for a minute until the soup is incorporated into a smooth puree. Here is a big secret – Once you have made the recipe, you know how thick it will be. If you wish, when making the soup, increase the amount of arrowroot for thickening, at the time of cooking, to get the desired thickness on the NDD diet. Otherwise, use one of the recommended thickeners to get the soup to the desired consistency. This soup has a tremendous amount of flavor and is excellent for those with swallowing or chewing difficulties.