Place diced pineapple in a mixing bowl. Set aside.
Pour about 2 ounces pineapple juice into a cup or small bowl. Add cornstarch. Stir well to dissolve the cornstarch.
Place a sauté pan over medium high heat.
Pour in remaining pineapple juice (without the cornstarch). Bring to a boil.
When juice is boiling add rum and banana liqueur.
Stirring rapidly with a whisk, add in the pineapple/corn starch mixture.
Keep stirring rapidly and add sugar.
When sugar has dissolved completely, remove from heat.
Add butter to still hot mixture. Stir to melt.
Pour mixture over the diced pineapple in bowl. Stir well to coat.
Place bowl in the refrigerator and allow to cool fully.
Prepare Mexican Restaurant-Style Empanada Dough according to the recipe linked to in the Box below. Set aside.
Pour oil into fryer or large cooking pot. Heat to 350°F.
On a flour surface, place 1-ounce ball of Mexican Restaurant-Style Empanada Dough. Roll, flatten and shape into a 6-inch round.
Place about 3 tablespoons of prepared pineapple filling mixture in the center of the round.
Fold over into a half moon shape. Crimp edges with a fork to seal.
Repeat with remaining empanada dough and filling.
Place prepared empanadas, a few at a time, in fryer. Cook until golden brown, about 3 minutes.
Remove to a paper towel-covered plate to drain.
Repeat with remaining empanadas.
Serve with ice cream, whipped cream and/or powdered sugar.