First pre-heat the oven to 350F. In a large bowl stir the cookie mix, cocoa & flour. Then add in the sour cream, 1/4 cup butter, 1 tps. vanilla & the egg. Mix until a stiff dough forms.
Next shape the dough into 36, 1 inch balls. Place on an ungreased cookie sheets. Then place the balls 2 inches apart. Then press each ball to flatten slightly.
Next bake for about 8 to 9 mins or until set. Make sure not to over bake. Cool for about 2 mins & then remove from cookie sheet to a cooling rack. Make sure to completely cool for about 15 mins.
Next in a small bowl beat filling ingredients with an electirc mixer until light & fluffy. Then spread about 2 tps of the filling on one cookie top. Then top with an other cookie bottom side down. Press gently to make the cookies to come together.
Then in a small bowl stir together the topping ingredients & sprinle over the tops of each cookie pie. Store between sheets of waxed paper in a tightly covered container.