Pineapple Upside Down Cake

in the egg whites until combined then beat in the sour cream and vanilla extract. Scrape down the sides and up the bottom of the bowl as needed. Pour the dry ingredients into the wet ingredients. Turn the mixer onto low speed and as the mixer runs slowly pour in the pineapple juice and milk. Beat on low speed just until all of the ingredients are combined. Do not overmix. You may need to whisk it all by hand to make sure there are no lumps at the bottom of the bowl. The batter will be slightly thick.
Remove topping from the refrigerator. Pour and spread cake batter evenly over topping.
Bake for 4348 minutes tenting foil on top of the cake halfway through bake time to prevent the top from overbrowning before the center has a chance to fully cook. The cake is done when a toothpick inserted into the center of the cake comes out mostly cleana couple moist crumbs are OK. Dont be alarmed if your cake takes longer or if the cake rises up and sticks to the foil. We serve the cake upside down anyway!
Remove cake from the oven and cool on a wire rack for just 20 minutes. Invert the slightly cooled cake onto a cake stand or serving plate. Some of the juices from the topping will seep over the sidesthats ok. You can slice and serve the cake warm but the slices will be messy. I find its best to cool the cake completely at room temperature before slicing and serving. Do not refrigerate the cake to speed up the cooling process because it could end up tasting overly dense.
Cover leftover slices and store for up to 3 days in the refrigerator or 3 months in the freezer. Thaw at room temperature. I dont recommend freezing the cake as a whole because the topping arrangement doesnt thaw very nicely. See make ahead instructions below.