Preheat oven to 350°F (175°C). Grease and line cake pans.
In a bowl, whisk flour, baking powder, baking soda, and salt.
In another bowl, beat butter and sugar until light and fluffy.
Add egg whites, sour cream, vanilla, and coconut extract; mix well.
Add dry ingredients alternately with coconut milk and pineapple juice.
Fold in shredded coconut and pineapple chunks.
Divide batter into pans and bake for 25–30 minutes. Cool completely.