Rinse the corn husks under running water, then soak them in hot water for about 1 hour. Place something heavy on top to keep them submerged.
In a mixing bowl, using a hand mixer (or by hand), beat the butter and vegetable shortening until light and fluffy. Add the sugar and salt, and continue beating until the mixture becomes very fluffy, similar to frosting.
Add the masa harina and rice flour. Switch to mixing by hand so you can feel the dough's texture. Gradually pour in the pineapple juice, followed by the crushed pineapple. Mix well to incorporate the liquids.
Add the baking powder and ground cinnamon. Beat the dough thoroughly so the tamales turn out light and fluffy. Drop a small piece of dough into a cup of water. If it floats, the masa is ready. If it sinks, beat the dough longer and test again.
Add a few drops of yellow food coloring until you reach your desired shade. Stir in the pineapple tidbits.
If the corn husks are short, overlap two husks for each tamal. Place a generous spoonful of masa in the center, fold the top husk over the masa, fold both sides inward, and tie loosely with a strip of husk so the tamal has room to expand while cooking.
Fill the steamer with hot water and add two clean coins. When the water is boiling, the coins will rattle; if the sound stops, the water level is low and needs more hot water. Line the bottom of the steamer with corn husks.
Stand the tamales upright inside the steamer. Add more husks around and on top. Cover with a clean kitchen towel, then place the lid on securely.
Once the water begins to boil, start timing. Steam the tamales for 1 hour and 15 minutes.
Turn off the heat and let the tamales rest for a few minutes before opening. Transfer them to a tray and cool for about 10 minutes. A properly cooked tamal will release cleanly from the husk. Serve.