1. In a small bowl, dissolve coffee granules in water.
2. Stir in the oats; set aside.
3. In a small mixing bowl, cream butter and sugars.
4. Beat in egg yolk and vanilla. Beat in reserved oat mixture. Combine the flour, cocoa, baking powder, baking soda and salt; add to oat mixture.
5. Stir in 1/3 cup chocolate chips.
6. Fill greased miniature muffin cups three-fourths full.
7. Sprinkle with remaining chips.
8. Bake at 359 degrees F for 12-15 minutes or until a toothpick comes out clean.
9. Cool for 5 minutes before removing from pans to wire racks.