Banana Coconut Upside Down Bundt Cake

Name: Banana Coconut Upside Down Bundt Cake
Prep time: 15 min
Cook time: 25 min
Total time: 40 min
Cuisine: Canadian
Ingredients: 1/2 cup unsalted butter; 5 medium ripe bananas (sliced 1 inch thick pieces); 1/2 cup brown sugar (packed); 1/4 teaspoon salt; 1/2 cup unsweetened shredded coconut; 2 Tablespoons lemon juice; 1/4 cup rum or gran marnier (*Optional*); 4 large egg whites (room temperature); 2 teaspoons vanilla sugar (1 envelope) (or 2 teaspoons vanilla extract); 1/2 cup white sugar; 4 large eggs yolks (room temperature); 1/2 cup + 2 Tablespoons all purpose flour; 1/4 cup cornstarch; 2 teaspoons baking powder; 1/3 cup unsalted butter (melted); 1/4 cup unsweetened shredded coconut; 1 Tablespoon powdered icing sugar