Position rack in center of oven. Preheat oven to 350°F/180°C.

Melt the butter in a 9-inch (23 cm) nonstick skillet over medium heat, then add the brown sugar, stirring to combine. Simmer for about 1 minute. Remove from heat and make sure mixture is spread evenly over the bottom of the pan. Arrange 6 pineapple slices around the edges and one in the middle (see image). Place one dried cranberry or fresh raspberry inside each pineapple ring, if using.

Vigorously whisk egg yolks and sugar together until combined, thickened and creamy. Whisk in the milk, then the flour, baking powder and salt until well combined.

Beat the egg whites in a clean, grease-free bowl with an electric mixer on high speed until stiff but not dry. Fold one-quarter of the whites (you can do this by eye) into the batter to lighten it, then fold in the rest. Pour batter over pineapple and spread evenly over fruit in pan.

Bake for about 35 to 40 minutes or just until a toothpick tests clean. Loosen the edges of the cake from the pan and invert onto a large, flat serving plate. If any pineapple, cranberries or raspberries stick to the pan, simply pry them loose and put them into place. Serve as soon as possible. Cake is best served the same day and may be served warm or at room temperature.