Stir brownie mix, oil, egg, and water together in a bowl until dough is thick and begins to pull away from sides of the bowl. Roll dough into 1-inch balls and place 2 inches apart on a baking sheet.
Bake in the preheated oven until just set in the center, 8 to 10 minutes.
Cool brookies on the baking sheet for 5 minutes; transfer to a wire rack. Sift confectioners' sugar over brookies and cool for 5 minutes more. Gently place 1 chocolate kiss in the center of each brookie.
