Cuban Boniatillo (Sweet Potato Paste Dessert) - cooking recipe

Ingredients

1 1/2 lbs cuban white sweet potatoes
1 teaspoon salt
2 cups water
2 cups sugar
1 cinnamon stick (about 2 inches or longer)
1 lime peel, of no pith, just the green part, use a vegetable peeler
3 large egg yolks, lightly beaten
1/4 cup dry sherry (I donA't use this, instead, I use vanilla)
2 teaspoons vanilla (see above) (optional)
1 teaspoon cinnamon (optional)
ground cinnamon (to garnish)

Preparation

Place the cubed potatoes in a large saucepan, cover with water and add 1 teaspoon salt - boil until tender, about 20 minutes.
Drain potatoes and puree in a food processor or blender.
Combine the 2 cups water, 2 cups sugar, lime peel and cinnamon stick in a large heavy saucepan.
Cook until it reaches the soft-ball stage (250 degrees) on a candy thermometer - about 15 minutes - stir frequently.
Reduce heat to low, carefully add potatoes cook and stir until smooth - about 6 to 8 minutes.
Remove from heat and add the egg yolks and mix well.
Return to low heat for 2 to 3 minutes stirring constantly.
Remove from the heat mix in either the sherry or the vanilla (NOT BOTH) Note: I like to add 1 teaspoon of cinnamon here, but it's optional.
Allow the paste to cool at room temperature for about 10 to 15 minutes.
Transfer to a serving bowl or individual dishes and refrigerate for at least 2 hours.
Sprinkle with cinnamon and serve cold.