1-1/2 cups fresh pineapple, cut into 1/2 inch pieces
3 tablespoons sugar, divided
1 to 2 tablespoons RumChata liqueur
1 teaspoon grated lime zest
1/2 cup heavy whipping cream
1 medium lime, thinly sliced, optional
In a large bowl, whisk flour, sugar, baking powder, salt and baking soda. Cut in butter until mixture resembles coarse crumbs. In another bowl, whisk egg, sour cream and RumChata. Add to flour mixture; stir just until moistened.
Spoon mixture into 6 greased half-pint jars. Center lids on jars and screw on bands until fingertip tight. Place jars in a 6- or 7-qt. oval slow cooker; add enough hot water to reach half way up the jars, about 5 cups. Cook, covered, on high until a toothpick inserted in center comes out clean, 1-1/2 to 2 hours.
Meanwhile, combine pineapple, 2 tablespoons sugar, RumChata and lime zest. Refrigerate, covered, at least 1 hour. Remove jars from slow cooker to wire racks to cool completely. In a large, beat cream until it begins to thicken. Add remaining 1 tablespoon sugar; beat until soft peaks form.
Top shortcakes with pineapple mixture, whipped cream and if desired, lime slices.