Heat oven to 350 degrees F. Oil and flour three 9-inch cake pans. Set aside.
In a large mixing bowl, cream sugar and oil until well blended.
Add eggs, one at a time, whipping after each addition.
In a separate bowl, combine flour, baking powder, baking soda, salt and
cinnamon. Add, a little at a time, into the egg mixture, blending well until
all is incorporated. Fold in the vanilla extract, pecans and mashed yams.
When all is well blended, pour evenly into the cake pans.
Bake for 40 minutes or until cake tester comes out clean.
While cake is baking, make filling by combining pineapple, sugar and cornstarch.
Bring to a low boil over medium-high heat, stirring constantly for 5 minutes.
When mixture has thickened, remove from heat and allow filling to cool.
In the bowl of an electric mixer, combine cream cheese, butter, confectioners
sugar and vanilla extract. Blend on low speed until well mixed. Whip until frosting
is fluffy and smooth.
Remove and set aside.
When cakes are done, remove from oven and allow to cool.
Remove cakes from baking pans and spread pineapple filling between layers.
Frost with the cream cheese frosting and serve.