While we think of sweet potatoes as a winter vegetable, they are actually grown in the summer. Shooting up green vines from the earth, each plant will yield up to 5 pounds of this sweet tuber. They last for months if stored properly in a root cellar. Two months after harvest, I'm still enjoying my stash that I brought back with me to Cambridge.
An interesting factoid about sweet potatoes: they actually get sweeter after they've been harvested. Once the plant is cut away, a chemical reaction occurs turning the starches into sugars. As such,the sweet potatoes need to cure for at least one week after harvesting before eating or cooking.
There are dozens of varieties of sweet potatoes — both white and orange. Typically, in New England, you'll find jewel. To hear Brett describe them, they are pure sugar. His favorite varieties are white hamon and beauregard. These offer sweet, nuanced and balanced flavor.
Here are some more thoughts from Brett about sweet potatoes:
Very large sweet potatoes are unjustly scorned by novices, but old-time Southern cooks treasure the mammoths for ease of use. They also know that a slowly grown but big sweet potato is more flavorful than a typical conventionally grown, smaller sweet potato whose growth was rushed and babied with agricultural chemicals.
Different sweet potato cultivars have markedly different flesh colors and flavors. The white types (actually beige, to my eye) usually have a nuttier, nuanced suite of flavors, and often a less creamy and more stringy texture, than the orange types. White Hamon is an exception, being both very sweet and creamy and with a unique beige-pale green flesh when cooked in certain ways. We will let you know the names of the types you are receiving. I personally prefer the white kinds for savory roasted uses and the orange types for pies, but there is naught more subjective than palate opinions.
Sweet Potato Vichyssoise is a fantastic summer-time chilled soup, but can also be served hot on a cold winter evening.
3 tablespoons butter
1 small onion, peeled and chopped
1 celery stalk
4 garlic clove
1/4 cup white wine
2 medium large sweet potatoes
4 cups water
2 leek — washed
1/4 cup cream
1. Heat pot over medium heat. Add 2 tbs. butter. Add onions, garlic, leeks and celery. Sweat for about 5 minutes. Deglaze with white wine
2. Add potatoes and water. Simmer for about 30 minutes, or until potatoes are tender.
3. Puree soup. Add cream. Season to taste with salt, pepper and lemon juice
4. Chill soup.
5. While soup is chillin', heat a large sauté pan over high heat. Add remaining butter, corn, shallots and garlic. Sauté without shaking the pan, for 3 minutes, or until the corn becomes sweetly aromatic. Season to taste with salt and pepper.
6. Puree chipotle peppers with 1/4 cup water and 1 tbs. red wine vinegar
7. When soup is chilled, garnish with
a- corn and a drizzle of the chipotle puree, or
b- spicy sausage and scallions