Because these cookies are large, give them plenty of space.

Step 2 – Cream the Butter and Sugars

In a large bowl, combine the softened butter, granulated sugar, and brown sugar.

Beat until creamy and well mixed.

You do not need to whip in a huge amount of air.

Step 3 – Add the Wet Ingredients

Add the egg and vanilla.

Mix until incorporated.

Add green gel food coloring a little at a time until the dough reaches a bold Halloween-green shade.

Step 4 – Add the Dry Ingredients

Add the flour, baking powder, and salt.

Mix just until a soft dough forms.

Avoid overmixing once the flour goes in.

Step 5 – Add Chocolate and Oreos

Fold in the semisweet chocolate chips, mini milk chocolate chips, chopped milk chocolate, and chopped Chocolate Oreos.

Make sure everything is distributed evenly.

Assemble the S’mores Centers

Step 6 – Build the Filling

On the prepared baking sheet, place:

1 whole Chocolate Oreo

1 square milk chocolate

1 marshmallow

Stack them neatly in that order.

Repeat to create 8 filling stacks.

Step 7 – Cover with Cookie Dough

Take a generous portion of cookie dough.

Flatten it into a thick disk, then wrap it around one s’mores stack.

Bring the dough up and around the filling until completely sealed.

Roll gently between your hands to smooth the outside.

Repeat with the remaining filling stacks.

Bake the Cookies

Bake for 12–15 minutes.

The edges should look set and lightly golden, while the centers remain soft.

The cookies may look slightly underbaked in the middle when they first come out, which is ideal.

Let them cool on the tray for 5–10 minutes.

Add the Halloween Eyeballs

While the cookies are still warm, gently press candy eyeball sprinkles into the tops.

Use different placements for each cookie to make them look like individual little monsters.

Let the cookies cool slightly before moving them.

The Secret to Keeping the S’mores Center Inside

The most important thing is completely sealing the filling.

Marshmallow expands and melts dramatically in the oven, so even a small gap in the dough can allow it to escape.

Use a thick layer of dough around the filling and pinch every seam closed.

Keeping the filling centered also helps the cookie bake evenly.

How to Know When the Cookies Are Done

Look for:

• lightly golden edges,
• tops that look mostly set,
• soft centers,
• and no visibly raw dough.

Do not wait until the entire cookie looks firm.

A slightly soft center gives you the best gooey texture once the marshmallow and chocolate inside melt together.