Delicious Apple Crumb Cake

I came across this apple cake on AllRecipes when looking for non-chocolate dessert recipe for my non-chocolate loving dad on Christmas Eve. It turned out absolutely delicious...moist and cinnamon-y, perfect for winter. It would be great served with vanilla bean ice cream.

1/4 cup butter-flavored shortening
1/2 cup sugar
1 egg
1/2 teaspoon vanilla extract
1 cup flour
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1/4 teaspoon salt
1/2 cup sour cream
1 chopped, peeled tart apple

For topping:
1/3 cup packed light brown sugar
1/2 teaspoon ground cinnamon
1 tablespoon cold butter
1/4 cup chopped walnuts

Preheat oven to 350 degrees.

Cream the shortening and sugar together in a large bowl with electric mixer. Add egg and vanilla extract. In a separate bowl, combine flour, baking powder, baking soda, and salt, and then add to the creamed mixture. Add sour cream and continue to mix. Stir in chopped apple, and transfer batter into greased 8" square or 9" round baking dish. For topping, combine brown sugar and cinnamon and then cut in butter till crumbly. Mix in nuts and sprinkle topping mixture over batter. Bake for 30 minutes or until a toothpick inserted in the middle of the cake comes out clean.