To prepare cookies: In a small bowl, dissolve instant coffee in water. In a medium saucepan over low heat, combine coffee mixture, pears, granulated sugar, butter, raisins, cinnamon, cloves and nutmeg. Simmer gently until pears are tender, about 4 to 5 minutes. Remove from heat and cool.
Preheat oven to 375 degrees and line baking sheets with parchment paper. When pear mixture is at room temperature, add 1 teaspoon vanilla extract. In a large bowl, blend flour, baking soda and salt. Add pear mixture and chopped walnuts; mix until just combined. Drop by heaping teaspoonsful onto prepared baking sheets and bake 12 to 14 minutes. Remove from oven, cool for 2 minutes and transfer cookies to a wire rack to cool completely.
To prepare icing: In a medium bowl, whisk together powdered sugar and butter, then add vanilla extract and coffee until smooth. Drizzle frosting on cookies, and top with walnut halves (or golden raisins or Craisins).