This cake is similar to carrot cake—grated sweet potatoes make it moist and rich. The cake can be made up to three days ahead, but frost and garnish it within 12 hours of serving.
1. To make Cake: Preheat oven to 350°F. Coat 10-inch round cake pan with cooking spray.
2. Place raisins in small bowl, and cover with boiling water. Let stand 10 minutes, then drain, and set aside.
3. Whisk together flour, baking powder, baking soda, salt, cinnamon, nutmeg, and cloves in bowl. Whisk together oil, brown sugar, and sugar in separate bowl; whisk in almond milk and lemon juice.
4. Stir flour mixture into oil mixture with spatula until thick batter forms. Fold in sweet potato, candied ginger, hazelnuts, and raisins. Pour batter into prepared pan, and bake 1 hour, or until toothpick inserted in center of Cake comes out clean. Cool pan 10 minutes on wire rack, then unmold Cake onto wire rack to cool completely.
5. To make Topping: Whisk together cream cheese, agave nectar, and vanilla in bowl until smooth; spread over cooled Cake. Decorate top of Cake with candied ginger and hazelnuts.