Melt chocolate chips in a heatproof bowl in a microwave 1-2 minutes or over simmering water until almost melted. Remove from heat and stir until smooth. In another heatproof cup, melt white chocolate chips and stir until smooth. Divide cookies in half. On one half, spread with melted chocolate and set on rack. Spoon white chocolate in a small plastic bag or parchment cone, cut tip and pipe a “bite” out of the eclipse. Before serving, spoon a heaping teaspoon of Fluff on a plain cookie and top with chocolate-covered top.