Combine sweet potato, sliced leek, and 1/4 cup broth in a 1 1/2-quart casserole; stir well. Cover, and microwave at HIGH 10 minutes, stirring after 5 minutes. Place sweet potato mixture in a blender or food processor; process until smooth. Add remaining ingredients except chopped leek; process 30 seconds or until blended. Garnish with chopped leek, if desired. Serve warm.
Very, very good soup. Don't be afraid of the mustard--it works perfectly. I used Zatarain's Creole Mustard, which is slightly sweet although it has no sugar, and was pretty liberal with the white pepper, though just a dash of nutmeg. I did saute the leeks first in a tsp. of canola oil, then added the sweet potatoes and broth, cooking gently until the potatoes were soft. Whirred them up in the food processor, then added the milk and seasonings. Used chopped chives on top. Served this with the turkey and wild rice salad from another issue of CL for a nice dinner.
First of all, why create a recipe that only makes 3 cups of soup? I quadrupled the recipe and got about 3 quarts of soup. I made changes: instead of the evaporated milk I used one can of lite coconut milk, I added a tablespoon of grated fresh ginger, I didn't even consider using the mustard (that made no sense to me), I sauteed the leeks in a tablespoon of canola oil, added the sweet potatoes and simmered with the stock - then pureed. Again, microwaving? Why? After my changes it actually came out very well.
This was quick and easy - excellent for a weeknight. I might use less or no mustard next time, but that might just be a personal preference. I think it is just personal preference, either way it's a great recipe.