If you’re looking for a fun and spooky treat to bake this Halloween, these Halloween Cookie Bars are just the thing. Think buttery shortbread-style bars topped with a rich, jet-black buttercream and finished with cute (and only slightly spooky!) white chocolate ghosts. They’re festive, eye-catching and the perfect centrepiece for a Halloween party table. Plus, they’re sturdy enough to cut into neat squares, making them ideal for sharing at school bake sales or trick-or-treat gatherings.

I love these cookie bars because they’re such a fun twist on a classic shortbread. They’re easy to make but look like you’ve gone all out with the decorations, which is always a win in my book.

Halloween cookie bar, a shortbread cookie bar with black buttercream and a white chocolate ghost topper

Why You’ll Love These Halloween Cookie Bars

A fun and spooky treat that’s perfect for Halloween parties.
Thick, buttery shortbread base that’s melt-in-the-mouth delicious.
Topped with jet-black buttercream for a dramatic effect.
Finished with cute white chocolate ghosts that kids (and adults!) will adore.
Easy to make ahead and decorate with the family.

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Ingredients Breakdown

Be sure to check the recipe card for a full list of ingredients and quantities.

Butter – gives the shortbread its rich flavour and tender crumb. Use unsalted for best results.
Caster sugar – sweetens the base while keeping it light. You could swap for golden caster sugar for a slightly caramel note.
Plain flour (all-purpose flour) – the backbone of the cookie bar, keeping it sturdy but still melt-in-your-mouth.
Cornflour (cornstarch) – optional, but adds softness and a delicate texture to the shortbread base.
Vanilla extract – enhances the flavour in both the base and the buttercream.
Icing sugar (powdered sugar) – for a smooth and fluffy buttercream.

Black food coloring – gel food colouring is best for that bold Halloween finish without thinning the icing. I like to use Colour Mill Black food colouring for a strong colour.
White chocolate – melted and piped to make the little ghost shapes. You could also use candy melts if you prefer.
Dark chocolate chips (optional) – perfect for adding little ghost eyes and mouths! If you’d rather, you could colour some of the white chocolate with the black food colouring and use that.

Step-by-Step Instructions

Make the shortbread base – Cream together butter and sugar until light and fluffy. Add flour, cornflour, and vanilla extract, mixing until it forms a soft dough.
Press and bake – Press the dough evenly into a lined 8-inch square tin and prick all over with a fork. Bake for 20-25 minutes until pale golden and set. Leave to cool completely.
Prepare the ghosts – Melt white chocolate and pipe blobs onto a baking sheet lined with parchment paper. Using a palette knife or the back of a spoon, press into the blob and drag the knife to smear the chocolate – don’t go too thin! Add tiny dark chocolate dots for eyes and mouths, or colour some white chocolate with black food colouring and use this. Let them set in the fridge.
Make the buttercream – Beat softened butter until pale and fluffy. Add icing sugar gradually, then vanilla and black gel food colouring until you get the perfect shade.
Assemble – Spread the black buttercream over the cooled cookie base while it’s still in the tin. Top with some optional Halloweeny sprinkles and your set white chocolate ghosts, spacing the ghosts evenly. Cut into squares and serve.

FAQ

Can I make these ahead of time?
Yes! The cookie bars will keep for up to 3 days in an airtight container. You can also prep the white chocolate ghosts the day before.

Do I have to use black buttercream?
Not at all – you could use orange or purple food colouring for a more colourful Halloween vibe, or pink for a pastel Halloween theme!

What if I don’t have a piping bag for the ghosts?
You can use a small sandwich bag with the corner snipped off to pipe the melted chocolate.