Preheat oven to 300 degrees. Take a piece of parchment paper and draw a circle about 9 or 10 inches on one side. Place the paper, drawn side down on a baking sheet.

Beat egg whites until soft peaks start to form. Gradually beat in the sugar, one tablespoon at a time. Beat until stiff and glossy. Beat in the vanilla, lemon juice, and cornstarch. Fold in ¾ cup of coconut flakes.

Spoon the mixture onto the parchment paper and, with the back of a large spoon, spread the meringue out to fill the circle and make a well in the center. Put in the oven and immediately reduce the temperature to 250 degrees. Bake for 1 hour. Turn off the oven, leave the oven door ajar and let the meringue cool in the oven.

Melt the butter in a large skillet over medium heat. Add the pineapple and cook, stirring once or twice, for 6-8 minutes or until starting to brown. Remove the pineapple from the skillet, add the brown sugar and 3 tablespoons rum and cook until bubbly, about 1 minute. Take off the heat, return the pineapple to the pan, stir to coat and let cool.

Beat the cream with the powdered sugar and 1 tablespoon rum until soft peaks form.

Spread the cream over the cooled meringue and top with the pineapple. Top with the remaining 1/4 cup coconut flakes.