Preheat oven to 325 degree. Spray 4 (9-inch) cake pans with baking spray with flour. Line bottoms of pans with parchment paper; spray again and set aside.

In a medium bowl, sift together flour, baking powder, baking soda, and salt; set aside.

In a separate medium bowl, combine butter and sugar. Beat at high speed with an electric mixer until light and fluffy, approximately 6 minutes.

In a small bowl, whisk together eggs, sour cream, and extracts; set aside.

With mixer at low speed, add flour mixture to butter mixture in 3 batches, alternating with egg mixture and beginning and ending with flour mixture. Beat until smooth. Spoon batter into prepared pans.

Bake until a wooden pick inserted near the center comes out clean, approximately 20 to 25 minutes. Cool in pans for 15 minutes; remove to wire racks to cool completely.

Once layers have cooled completely, spread Coconut Filling between layers. Frost sides and top of cake with 8-Minute Coconut Frosting. Immediately cover sides and top of cake with coconut, pressing gently to adhere. Cover and store in refrigerator for up to 3 days or freeze for up to 1 month.

In a double boiler over simmering water, combine sugar, cream of tartar, salt, water, and egg whites. Beat on high speed with an electric mixer for 8 minutes. Add extracts, beating to combine. Use immediately.

In a medium saucepan, bring condensed milk and butter to a boil over medium-high heat. Remove from heat. Pour approximately 1/2 cup milk mixture into yolks, whisking constantly. Add yolk mixture to saucepan, whisking to combine. Add coconut and extract, stirring to combine. Cover and refrigerate for 1 hour.