Chewy brownie-cookie bars that kids can bake and decorate like spooky monsters, ghosts, and pumpkins. Easy, festive, and perfect for parties.

Scale

1 box (18–19 oz) brownie mix, plus eggs, oil, and water per package

16 oz refrigerated cookie dough (chocolate chip or sugar cookie)

1/2 cup chocolate chips or M&Ms (optional)

1 cup frosting in Halloween colors (orange, green, purple, black)

Candy eyeballs

Assorted toppings: gummy worms, candy corn, sprinkles

Nonstick spray or parchment paper

1. Preheat oven to 350°F (175°C). Grease or line a 9×13-inch pan.

2. Prepare brownie batter as directed on the box; spread evenly in the pan.

3. Pinch off cookie dough and dot pieces over the brownie layer; press lightly.

4. Sprinkle chocolate chips or M&Ms on top if using.

5. Bake 30–35 minutes, until set and a toothpick comes out with moist crumbs.

6. Cool completely in the pan on a rack before decorating.

7. Cut into bars or use cookie cutters for fun shapes.

8. Decorate with colored frosting, candy eyeballs, and toppings to make monsters, ghosts, and pumpkins.

9. Let frosting set 10 minutes. Serve or store airtight up to 3 days.