Heat oven to 350ºF. Grease bottoms and sides of 2 round pans, 9x1 1/2 inches, with shortening; lightly flour.
In large bowl, mix flour, granulated sugar, baking powder, baking soda, salt and cinnamon.
Add sweet potato, oil, 1 teaspoon vanilla, the eggs and pineapple with juice. Beat with electric mixer on medium speed 2 minutes. Stir in cranberries. Pour into pans.
Bake 25 to 35 minutes or until toothpick inserted in centre of cake comes out clean. Cool 5 minutes; remove from pans to wire rack. Cool completely, about 1 hour.
Fill layers and frost side and top of cake with frosting. Garnish edge with additional dried cranberries if desired. Store covered in refrigerator.