NOTE: Purchase the crushed pineapple in heavy syrup, because this makes a difference in the flavor of the cake. If it's in it's own juice, the cake won't be as flavorful. The can size may vary, but it's close to 15 ounces, although it may read 14.5 ounces, or 16.25 ounces. It will still be fine to use, as long as it's in the heavy syrup. ALSO: You can also use crushed pecans in the Frosting if you prefer those to Pretzels.