Ahead of time, soak 20 corn husk in really hot water, set aside. They should soak for at least an hour.
In the stand mixer, whip together the butter and shortening until fluffy. Mix in the sugar. baking powder and salt. Gradually mix in the masa harina. Then gradually mix in the water or juice. Once incorporated really well, mix on med/high speed for 7-8 minutes or until masa looks light and fluffy.
Fold in the preserves and diced pineapple. If adding in the pecans, coconut or raisins, add them now. Or leave as is for pineapple only tamal.
Shake off excess water from corn husk and fill them with about 3-4 tablespoons of pineapple masa filling down the center. fold in the sides, then fold down the flap. Fill steamer pot with water to the rim at the bottom. Add steamer insert. Place a few extra corn husk to the bottom of steamer pot, Arrange tamales standing up, with the open side up. Cover tamales with extra corn husk and a clean kitchen towel. Cover with lid.
Place steamer pot on high heat, to start. After about 10-15 minutes when it begins to steam rapidly, lower heat to below medium. Set timer for 45 minutes. Check one tamal after that time. Let it cool for a few minutes before attempting to open. If the husk peels away easily, then the tamales are done. If not, steam for another 15 minutes. Let them sit off the heat for 25 minutes more.