Add a burst of flavor and health to your cheesecake by adding yams, which are a valuable source of beta carotene.
Preheat oven to 375 degrees Fahrenheit. Place yams in a baking sheet and brush with 1 tablespoon melted butter. Bake until soft, about 40 minutes.
To make the crust:
Finely grind pecans and graham crackers in a food processor until the mixture resembles coarse sand. Mix in 2 tablespoons natural sugar and 4 tablespoons melted butter. Press mixture evenly onto bottom of 9-inch springform pan. Cook in oven for 10 minutes.
To make the cheesecake batter:
Place cooked yams in food processor and blend with lemon juice until they are a very smooth consistency. Reserve 1 cup for use, save extra for another use.
Reduce oven temperature to 325 degrees Fahrenheit. In a large mixing bowl, beat cream cheese until fluffy. Gradually add 3/4 cup natural sugar and brown sugar and blend until smooth. Beat in eggs one at a time, add reserved yam mixture, 1/4 cup whipping cream, sour cream, 1/4 cup maple syrup, cinnamon, nutmeg and cardamom. Mix until well blended.
Wrap bottom of cheesecake pan with heavy-duty foil, completely covering bottom and sides. Pour batter over crust. Put cheesecake pan inside a roasting pan and place in oven. Fill roasting pan with water until it comes halfway up the sides of the cheesecake pan.
Bake about 50 minutes, until cake barely jiggles when gently shaken. Remove cheesecake from roasting pan and allow to cool on a wire rack for about an hour. Place uncovered into refrigerator until completely cool, then cover with plastic wrap.
In a small mixing bowl, beat 3/4 cup whipping cream until stiff peaks form, add 1/4 cup maple syrup and Grand Marnier and mix until blended.