With a wooden spoon, mix butter into the mashed bananas in a large mixing bowl. Mix in the sugar, egg, vanilla and bourbon, then the spices. Sprinkle the baking soda and salt over the mixture and mix inches Add the flour last, mix. Finally stir in the chocolate chips.
Pour mixture into a buttered 4×8 inch loaf pan. Bake for 50 minutes to one hour, or until a tester comes out clean. Cool on a rack. Remove from pan and slice to serve.