What You Need:
- 1 large sweet potato
- 1 vanilla bean
- 1 cup sugar
- 3 1/2 cups heavy cream
- 1/2 teaspoon orange zest
- 1 teaspoon cardamom seed
- 1/2 teaspoon ground nutmeg
- 1 cup whole milk
- 7 teaspoons unflavored gelatin
Bake sweet potato in center of 325 degree oven until tender, about 1 hour. Peel and puree until smooth. Set aside.
Split vanilla bean lengthwise and scrape out seeds. Rub seeds into the sugar to distribute evenly. Remove the pod.
In a heavy saucepan, combine cream, sugar mixture, sweet potato puree, vanilla bean pod, orange zest, cardamom seed and nutmeg. Heat to scalding. Remove from heat and let mixture steep for 30 minutes.
In another heavy saucepan, combine milk and gelatin. Stir to dissolve. Add sweet potato mixture and heat to scalding, stirring constantly. Remove from heat; strain mixture through a fine sieve. Cool until mixture just begins to thicken and set.
Divide mixture among 10 6-ounce ramekins. Cover and refrigerate overnight.
To remove panna cotta, run the tip of a warm paring knife around the outside of the panna cotta. Invert the ramekin and wiggle to release. Server with lemon grass soup.
Makes 10 servings.
Lemon Grass Soup: Combine 4 cups heavy cream, 1 1/2 cups sugar, 6 stalks of fresh lemon grass and seeds scraped from 2 vanilla bean pods in a heavy saucepan. Bring mixture to a scald; reduce temperature and let simmer for 10 minutes. Remove from heat and let cool for 30 minutes. Strain mixture through a fine sieve. Refrigerate for at least 4 hours.