Preheat oven to 350°. In a small bowl, dissolve coffee granules in hot water. In a large bowl, cream butter and sugar until light and fluffy. Add egg; beat well. Beat in bananas, vanilla and coffee mixture. Combine flour, baking powder, baking soda and salt; add to creamed mixture just until moistened. Fold in chocolate chips.
Fill paper-lined muffin cups two-thirds full. Bake 18-20 minutes or until a toothpick inserted in muffin comes out clean. Cool 5 minutes before removing from pans to wire racks. Serve warm.
Decorative cupcake liners can be found at fancyflours.com.