Preheat oven to 350°F. Line and grease a 13x9x2" baking pan.

Whisk together flour, baking powder, and salt.

In a separate bowl, whisk egg yolks, 1/2 cup sugar, oil, and water.

Combine wet and dry ingredients; stir in coconut.

Beat egg whites until soft peaks form, gradually adding remaining 1/4 cup sugar.

Fold meringue into the batter and pour into the prepared pan.

Bake for about 30 minutes or until a tester comes out clean.

Cool cake in the pan.

Combine pineapple, sugar, and water in a saucepan and bring to a boil.

Puree the mixture in a blender until smooth.

Strain the puree to extract liquid; discard solids.

Stir in rum and lime juice.

Process the mixture in an ice cream maker to make pineapple sorbet.

Preheat oven to 325°F.

Combine sugar, salt, and water in a saucepan and bring to a boil.

Stir in macadamia nuts and cook for 5 minutes.

Strain nuts and bake on parchment paper for 10-12 minutes until golden.

Let cool completely.

Beat egg whites with cream of tartar until foamy.

Gradually add sugar, then rum and xanthan gum (optional).

Continue beating until firm peaks form for meringue.

Invert cake and cut into 6 rounds using a ramekin as a guide.

Spoon sorbet into ramekins, top with cake rounds, and freeze for 4 hours.

Run a knife around the ramekin edges, invert, and cover with meringue.

Freeze again for 30 minutes.

Preheat oven to 450°F.

Bake the cakes until meringue is toasted (1-2 minutes).

Spoon passion fruit juice and pulp around the plate, garnish with lime zest and macadamia nuts.