CAKE:

1 1/2 c. cake flour
1/2 tsp. baking soda
1/2 tsp. salt
1/2 tsp. ground cinnamon
1/2 tsp. ground nutmeg
1/2 c. (1 stick) unsalted butter, room temp.
1/2 c. sour cream, room temp.
1 1/4 c. + 2 tbsp. sugar
3 eggs, room temp.
1 (8 oz.) sweet potato, baked, peeled, pureed
1 tsp. vanilla extract

If time is short, use well-drained, mashed canned sweet potato in the cake.

CINNAMON SAUCE:

2 c. milk
1/4 tsp. cinnamon
1 tsp. vanilla
4 egg yolks
1/2 c. sugar
1/4 c. sour cream

TOPPING:

Praline or toffee ice cream

CAKE: Preheat oven to 350 degrees. Lightly oil 8 1/2" x 4 1/2" x 2 5/8" loaf pan. Sift first 5 ingredients into medium bowl. Using electric mixer, beat butter and sour cream in large bowl until well blended. Gradually add sugar and beat until mixture is light and fluffy. Add eggs, one at a time, beating well after each addition. Mix in 1/2 cup sweet potato puree and vanilla. Stir in dry ingredients. Transfer to prepared pan. Bake until tester inserted into center comes out clean, about 1 hour 15 minutes.

Cool cake in pan on rack 30 minutes. Cut around sides of pan with knife. Turn cake out onto rack and cool. (Can be prepared 1 day ahead. Wrap tightly with foil and let stand at room temperature.)

SAUCE: Combine milk and cinnamon in heavy medium saucepan. Add vanilla. Bring to boil. Remove from heat. Cover and let steep 15 minutes.

Whisk yolks and sugar in bowl to blend. Slowly beat milk mixture into egg mixture. Strain custard into same saucepan. Cook over medium low heat until custard thickens and leaves path on back of spoon when finger is drawn across, stirring constantly, about 15 minutes; do not boil. Pour custard into bowl. Whisk in sour cream. Cover and chill until cold, stirring occasionally. (Can be prepared 1 day ahead.)

Cut cake into slices and transfer to plates. Top with ice cream and sauce.