Cream together brown sugar, sugar, butter shortening, eggs and vanilla.
Then add in the flour, baking powder, baking soda, salt, and drained crushed pineapple. Stir together until blended.
Drop dough onto ungreased cookie sheet, or line your cookie sheet with a silpat baking sheet. If your dough is thick enough you could also roll it into 1 1/2 inch balls. Bake at 400 degrees for about 10 minutes.
Cool completely.
Frosting
Mix softened butter with powdered sugar.
Add in about 2 Tablespoons pineapple juice that you reserved from the crushed pineapple and vanilla. If you need to thicken up the frosting add more powdered sugar. If it's too thick add a little more pineapple juice.
Spread frosting on cooled cookies. Top with drained crushed pineapple.
Notes
For this recipe, it calls for butter flavored shortening. You can replace the shortening with butter, but your results will differ.