Prepare a food processor and pour the chopped pineapple. Afterward, process until it becomes finely pureed and transfer into a small saucepan. Bring the mixture to a boil over medium-low, and simmer. After that, stir occasionally and let the mixture reduce to about 2/3 of a cup. Afterward, set aside to cool completely.
Next, prepare a stand mixer attached with a paddle attachment. You can also use an electric mixer. Then, please set it to medium-high speed, and beat the mixture until smooth. Afterward, add in the vanilla extract and salt and continue to beat until everything incorporates well.
After that, add 2 cups of powdered sugar and meringue powder to the mixture. Then, beat at medium-low speed until most of the sugar becomes saturated. Afterward, gradually add the remaining sugar one cup at a time. So with that, you may need more sugar or less depending on how soft your butter will be.
Afterward, beat the mixture at medium-low speed until the sugar moistens. And then, ensure to set the mixer to medium-high speed and beat until the mixture becomes light and fluffy. Scrape the bowl's sides using a rubber spatula as needed to combine properly.
Lastly, add in the pineapple puree and beat until well combined.