Position your oven rack in the lower third of the oven and preheat to 350°F (177°C).

Begin by preparing the pineapple. Cut off both ends and remove the outer skin. Slice the pineapple into four long wedges, trimming away the tough core. From two of the wedges, cut 1/2-inch thick slices. These slices will be arranged in the cake.

Take 4 tablespoons of the softened butter and spread it evenly over the bottom of an 8 or 9-inch cake pan with at least 2-inch tall sides.

Next, sprinkle the brown sugar and cinnamon evenly over the butter layer.

Carefully arrange the pineapple slices over the butter and sugar mixture, ensuring they are in a single, even layer.

In a large mixing bowl, beat the remaining 8 tablespoons of butter along with the granulated sugar and citrus zest. Use an electric mixer on high speed for about 2 to 3 minutes until the mixture turns light and fluffy.

Add in the egg yolks and vanilla extract, continuing to beat until everything is smooth and fully incorporated.

In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add half of this flour mixture to the butter and egg yolk blend, mixing on low speed until only small streaks of flour remain. Then, mix in the remaining flour.

Without whipping, add the egg whites and sour cream to the batter. Gently mix on low speed until everything is fully combined and smooth.

Carefully spoon the batter over the pineapple slices in the cake pan, spreading it out evenly to ensure it covers the fruit layer.

Bake the cake for 35 to 40 minutes, or until a toothpick inserted into the center comes out clean.

Once baked, allow the cake to cool in the pan for 5 minutes. Run a knife along the edges to loosen it, then invert the cake onto a serving plate. If any pineapple slices stick to the pan, use a spatula to lift them and place them back on the cake, spreading any remaining brown sugar syrup over the top.