Preheat the oven to 350°F/180°C/Gas 4. Spray a 9-inch cast-iron skillet with nonstick baking spray.

Use an electric handheld or standing mixer to cream butter, white sugar, and brown sugar together in a bowl. Continue to beat with the electric mixer while adding the egg and pure vanilla extract.

In another bowl sift or whisk the flour, baking soda, and salt together.

Slowly add ⅓ of the flour mixture at a time to the wet ingredients. Beat to combine between each addition. You will form a soft dough.

Add 1 ½ cups of Halloween sprinkles to the cookie dough and fold to combine.

Transfer the cookie dough to the prepared skillet and press to evenly cover the whole pan.

Spread the remaining ½ cup of the sprinkles over the top of the unbaked cookie.

Place skillet into the preheated oven and bake for 35-45 minutes until golden.

Set aside to cool completely before decorating.

To make the frosting, use an electric handheld or standing mixer, and beat the butter, powdered sugar, vanilla, and heavy whipping cream together, until combined, smooth, and can hold stiff peaks.

Scoop 1 cup of frosting into a small bowl and mix in a little orange food coloring gel and mix to reach the desired shade. Remember you can always add more coloring but not take it away!

To the remaining frosting, add black food coloring gel, and mix to reach the desired shade. Making black can be tricky, to overcome this, if suitable I add a spoonful of dark cocoa powder to the frosting mix to help darken it.

Place ½ cup of black frosting into a piping bag fitted with a round no. 2 tip. Set it aside.

Place ½ cup of black frosting into a piping bag fitted with a round no. 4 tip. Set it aside.

Place the orange frosting into 1 one-half side of a piping bag fitted with a star tip. Place the rest of the black frosting into the other half side of the piping bag. Squeeze out a little frosting onto a plate to make sure the colors combine. Set piping bag aside.

Using the black frosting in the piping bag and tip no. 4, pipe a crooked hill for the tree to sit on, then pipe the crooked truck of a tree, and pipe out branches of varying thickness and curl to give them a creepy look. Fill in the shape of the tree and use a small angled spatula to smooth the frosting. Use the image below as a guide to pipe the haunted tree onto the top of the cooked and cooled cookie.

Using the black frosting in the piping bag and tip no. 2, pipe the outline of some bats and fill in with frosting. Smooth with a small angled spatula as before.

Use the orange and black frosting piping bag to pipe stars around the edge of the cookie.

Allow the frosting to harden slightly before serving. Enjoy and Happy Haunting!