I borrowed this recipe from another lovely lady on this site, because it sounded so yummy. I do cupcakes mostly so I took the recipe and tweaked it a little and adapted it for a cupcake. I eliminated a small amount of the juice from the pineapple and replaced it with 1/2 cup of melted butter. I also substituted 1/2 c. of packed brown sugar for 1 cup of the regular sugar. I also used brown butter buttercream frosting only because I am not that fond of cream cheese frosting. These cupcakes are to die for!!
Combine dry ingredients in a large bowl. Add vanilla and eggs and mix. This can be done by hand. Add the pineapple and butter and mix well. Add nuts and mix well. Pour into prepare cupcake papers.
For the frosting. Put one stick of the butter into a pan or small skillet and brown over low/medium heat until light brown. About 8 minutes. Set aside and cool thoroughly.
In a large bowl, beat the other softened stick of butter for approximately 30 seconds with mixer on medium speed. Add the cooled brown butter and beat together well. Add the vanilla and the sugar and continue to beat. Adding 1T of buttermilk at a time, beat in until the frosting is the desired spreading consistency. If frosting is still too stiff with 3T. of buttermilk, up to 3 more can be added. Too much, just add a little additional sugar until desired consistency is achieved.