Preheat the oven to 350°F/180°C/Gas 4. Spray a 8-inch cast-iron skillet with nonstick baking spray.

Use an electric handheld or standing mixer, beat the rolled oats, flour, brown sugar, baking soda, salt, canola oil, eggs,
and vanilla until combined and a soft dough forms. Fold in the chocolate chips.

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

Place skillet into the preheated oven and bake for 20-30 minutes until light golden brown.

Set aside to cool completely before decorating.

Drizzle the caramel and chocolate sauce on top of the cooked and cooled cookie.

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

Divide the frosting into two bowls.

Mix a few drops of black food coloring to one of the bowls of frosting 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 the black frosting in a piping bag, and the white frosting into another piping bag. Cut off the tips of the piping bags.

Using the black frosting, pipe a large vertical cross (+) and a diagonal cross (X) across the cooked and cooled cookie.

Pipe half circles between each line segment to finish the web detail.

Use the white frosting to highlight the web.

Using the black frosting, pipe out some spiders to go on the web - pipe a large circle and a small circle, and pipe 8 legs on each side as shown.

Cut into slices to serve. Enjoy and Happy Halloween!