Grease a 9-inch tube pan. Line it with brown paper. Grease the paper.
With a mixer on medium speed, cream the sugar and butter until fluffy.
Add the egg yolks and beat well. Set aside.
In another medium bowl, combine flour, salt, and baking powder.
On lowest speed, add it to the egg mixture.
Beat in the milk, rum extract, vanilla, raisins, walnuts, cherries, and pineapple. Put this batter into another bowl.
With a mixer on highest speed, beat the egg whites until stiff.
With a rubber spatula, gently fold the egg whites into the batter.
Pour the batter into the prepared pan.
Bake at 325° for 1½ hours or until a cake tester inserted comes out clean.
Immediately turn the cake pan over and remove the paper. Turn the cake pan back right side up and continue cooling the cake in the pan on a wire rack for 20 minutes. Meanwhile make the glaze while the cake is cooling.
GLAZE: Mix the butter, water, and sugar in a medium saucepan on top of the stove. Over low heat, keep stirring until the glaze reaches a boiling point.
Reduce the heat and simmer for 5 minutes until it gets thick. Add the rum or brandy.
Poke holes all over top of cake with a skewer. Spoon the glaze over the warm cake in the pan. Let the glaze seep into the holes.
Completely cool the cake on the wire rack.
Run a knife around the edges of the pan to loosen the cake.
Place a large piece of cheesecloth that has been doused in rum or brandy on a board.
Invert the cake onto the doused cheesecloth. Wrap the cheesecloth around the cake.
Carefully put the wrapped cake into a tin. Cover the tin.
The cake is better if it has been preserved in the doused cheesecloth in the tin for a few weeks, even a month! If you want, you can rewrap the cheesecloth after a few weeks in a new doused cheesecloth.