Preheat the oven to 350 degrees F. Coat a 9-inch round cake pan with cooking spray. Spread the brown sugar evenly over the bottom of the pan and drizzle evenly with the caramel topping. Top with the pineapple slices in a decorative pattern. Sprinkle with the cranberries and 2 Tablespoons of the saved pineapple juice. Set aside.
Place the egg whites and salt in a large bowl. Beat with an electric mixer until soft peaks form. Beat in vanilla. Gradually beat in the sugar until the whites are stiff, but not dry.
Sift together the flour and baking powder. Sift half of the flour over the egg whites. Gently fold in with a large rubber spatula
Fold in 1/4 Cupof the saved pineapple mixture. Sift the remaining flour over the egg whites and fold in.
Spread the batter evenly over the pineapple mixture.
Bake for 30 - 35 minutes, or until a wooden pick inserted in the center comes out clean.
Cool in the pan for 2 minutes, invert onto a serving plate. Cool for at least 1 hour before serving, if you can wait that long!!