In a stand mixer or working with pastry cutter, mix butter, flour and salt until dough becomes crumbly.
Add water, two tablespoons at a time, until consistency is smooth.
Wrap dough in plastic wrap and chill for 30 minutes.
Roll out dough on cutting board and cut 3-inch circles using a scalloped cookie cutter.
Place into greased cupcake pan, pressing sides of dough to fit.
Preheat oven to 400 degrees.
Combine all filling ingredients in a heavy non-aluminum saucepan. Cook over medium-low heat, stirring constantly until butter is melted and mixture thickens slightly. Do not allow to boil.
Remove from heat and transfer to a bowl to cool. Pour filling into dough cups and bake 15-18 minutes.
Let cool, then top with whipped topping. Refrigerate any leftovers.