Preheat your oven to 350 degrees F (180 degrees C) and place rack in the center of the oven.

Butter (or spray with a non stick vegetable spray) a 9 inch (23 cm) round cake pan with 2 inch (5 cm) sides.

Place the butter and brown sugar in a small saucepan and stir over medium heat until the butter has melted and the sugar has dissolved.

Continue cooking, without stirring, for a few more minutes or until bubbles just start to appear around the outside edges of the mixture (the sugar starts to caramelize).

Remove from heat, and pour into your prepared cake pan.

Evenly arrange the pineapple slices on top of the sugar mixture.

If you like, place a Maraschino Cherry in the center of each pineapple slice.

In a large bowl, sift or whisk together the flour, baking powder, and salt.

In the bowl of your electric stand mixer, fitted with the paddle attachment (or with a hand mixer), beat the butter, sugar, and vanilla extract until light and fluffy.

Add the egg yolks and beat until incorporated.

Add the flour mixture (in three additions), alternately with the milk (in two additions), ending with the dry ingredients (the batter will be thick).

In a clean bowl, whisk the egg whites with the cream of tartar just until the whites hold a firm peak.

With a large spatula gently fold the beaten egg whites into the cake batter in two additions.

Pour the batter into the cake pan, smoothing the top with the back of a spoon or offset spatula.

Bake in preheated oven for 35 - 45 minutes, or until the top of the cake is a deep golden brown and starts to pull away from the sides of the pan.

Remove from oven and place on a wire rack to cool for about 10 minutes.

Run a sharp knife around the edge of the pan and then invert the cake onto your serving plate.

Serve warm.