Sweet Potato Bisque

I wasn’t kidding when a while back I suggested sipping soup from a cup. At the moment it’s darn cold on this side of the equator and soup is a good choice for tea. Maybe instead of serving hot tea, serve something more refreshing like iced tea or Arnold Palmers (half iced tea half lemonade).

The first time I had sweet potato bisque was at the Village Inn in Monte Rio, our favorite place to stay when we are visiting the Russian River. It was so good I was determined to recreate it at home, but couldn’t get it quite right. The other night, as I found myself staring at two sweet potatoes all alone at the bottom of the potato bin, I thought I’d give it another try. Rather than over think it and run out to the store for fresh everything, I decided to use only what I had on hand. That meant dried herbs and an ad hoc vegetable stock. I just happened to have a little tub of crème fraîche in the fridge.

Until I worked on this recipe, I didn’t really notice (or care about) the difference between sweet potatoes and yams. Yams aren’t as common in the U.S. as sweet potatoes, and what most people call yams are actually sweet potatoes. For a better overall understanding of the two you can go here. And if you love vegetables and are at all interested in the origin, classification, varieties and preparation of all things veg, I highly recommend The Vegetable Book by Colin Spencer; it’s a book that makes you realize good writing doesn’t need photographs to accompany it.

Back to the bisque…

What you want for this recipe looks like what you see in the photo below, and should be readily available in most markets. In the U.S. they’re called garnet or jewel sweet potatoes (they might be labeled yams), but any orange fleshed tuber that looks like these should do.

Sweet Potato Bisque (makes 8 cups, about 4 servings)

2 large sweet potatoes, peeled and cut into 1 inch pieces (about 5 cups or 1 liter 240 ml )
1 medium onion, chopped (about 1-1/2 cups or 360ml)
3 Tbsp. (42g) unsalted butter
2 cloves garlic, minced or crushed
1 large carrot, cut into several pieces
1 large celery rib, cut into several pieces
2 fresh bay leaves
1/2 teaspoon (2.5ml) dried ground sage
1/4 teaspoon (1.25ml) dried ground ginger
1/4 teaspoon (1.25ml)  ground nutmeg
1/4 teaspoon (1.25ml) cayenne pepper or red pepper flakes (if you want a bit of kick, otherwise maybe just a pinch or leave it out altogether)
1/4 teaspoon (1.25ml) freshly ground black pepper
Several sprigs of fresh parsley
1/2 (2.5ml) teaspoon salt
Salt and pepper
4 cups (1 liter) water
1/4 cup (60ml) crème fraîche, sour cream, cream or half and half (the crème fraîche and sour cream will give it more tang)

I didn’t have vegetable or chicken stock on hand when I was making this soup, so I used water and added large chunks of celery and carrot to flavor the soup, but removed them prior to blending. You can leave the carrot if you want, but the celery will add a stringy texture to the soup even when blended. As for the size and quantity… What exactly is a large celery rib? When in doubt add more rather than less, and the flavor of the resulting soup will be better.

In a medium stock pot, over medium heat, cook the onion in the butter until soft and lightly golden, about ten minutes.

Add the garlic and cook about one minute.

Add the ginger, sage and nutmeg, and cook one minute.

Add the sweet potatoes, carrot, celery, parsley, bay leaves. Add the water and stir everything well, scraping any brown bits off the bottom. Add the 1/2 teaspoon salt and 1/4 teaspoon black pepper.

Simmer until the sweet potatoes are very tender, about 30-40 minutes. You should be able to easily mash the sweet potato with a fork. Remove the bay leaves, carrots and celery.

Using either an immersion blender or a regular blender, whiz the soup until it is smooth.

Add the soup back to the pot and add the crème fraîche, whisking until blended. Serve immediately. If you need to reheat the soup, and you’ve used sour cream, cream or half and half, don’t boil the soup or the dairy will separate. Crème fraîche can handle the heat without separating.

I garnished with a dollop of crème fraîche, black pepper, hazelnut oil and some tiny sage leaves fried in olive oil for about 30 seconds. Chopped fresh herbs like parsley or chives would also be nice.

I served the soup with a side of bite size grilled cheese sandwiches.