In a medium bowl, whisk the egg. Stir in contents of sugar cookie mix pouch and melted butter. Mix until a thick dough forms. Remove ¾ cup of dough to a smaller bowl and set aside.
Press remaining dough into a greased 9x9 square baking pan. In a separate bowl, stir together cherry pie filling and vanilla extract. Spread the topping over sugar cookie dough in a baking dish
Break up remaining dough into small chunks and sprinkle over top of cherry pie filling. Bake at 375 for 20-30 minutes, or until edges are golden brown. Cool before slicing and serving.