Baked Hawaiian Islands

Name: Baked Hawaiian Islands
Ingredients: Unsalted butter (for pan); 2/3 cup all-purpose flour; 2 teaspoons baking powder; 1/2 teaspoons kosher salt; 4 large eggs, separated; 3/4 cup sugar, divided; 1/2 cup vegetable oil; 1/2 cup unsweetened shredded coconut; 6 3/4 cups 1/2 cubes fresh pineapple (cut from two 4-pound pineapples); 3/4 cup (packed) dark brown sugar; 3 tablespoons dark rum (such as Gosling's); 3 tablespoons fresh lime juice; 1/4 cup sugar; 2 teaspoons kosher salt; 1/2 cup whole macadamia nuts; 1 cup egg whites (from about 7 large eggs), room temperature; 1/4 teaspoon cream of tartar; 3/4 cup sugar; 1 teaspoon coconut rum (such as Malibu); 1/8 teaspoon xanthan gum (optional); 4 ripe (wrinkled) passion fruits, halved, pulp scooped out; 2 teaspoons finely grated lime zest; Ingredient info: Unsweetened shredded coconut is sold at specialty foods stores and at natural foods stores. Xanthan gum adds an extra-creamy texture to the meringue; it's sold at better supermarkets, natural foods stores, and bobsredmill.com.; An ice cream maker; six 8-ounce ramekins