Preheat the oven to 350 degrees
Using a double broiler, melt 12 tablespoons (1 1/2 sticks) of butter and 6oz of white chocolate
Once the butter and white chocolate have melted, remove them from the heat and allow them to cool a bit
Divide the eggs and place the yolks in a large bowl and the whites into a mixing bowl
Add a pinch of salt to the egg whites and whip them either using an electric hand mixer or a stand mixer with whisk attachment until stiff glossy peaks have formed and then set aside
Add 2/3 cup of sugar to the egg yolks and whisk them until they have lightened to a pale yellow
Add 1/3 cup of citrus juice, 2 tablespoons of citrus zest, the vanilla and citrus extracts and whisk until fully combined
Add the melted butter and white chocolate and whisk to combine
Add the almost flour and whisk to combineĀ
Gently fold in the whipped egg whites, one third at a time, until everything is fully combined and batter is light and airy
Place a greased 9" springform pan over a baking sheet and transfer the batter into the pan
Bake at 350 degrees for 40 minutes or until a toothpick comes out from the center clean
Transfer the springform pan onto a cooling rack for 10 minutes
Gently release the side of the springform and allow the cake to cool fully