• In a mixing bowl, whisk together the flour and baking powder. Set aside.
• In another bowl, using an electric mixer, cream together the softened butter and granulated sugar until light and fluffy.
• Add the egg and vanilla extract to the butter-sugar mixture. Beat until well combined.
• Gradually add the dry ingredients (flour and baking powder mixture) to the wet ingredients, mixing until a smooth cookie dough forms.
• Roll out the cookie dough between two sheets of parchment paper to your desired thickness. Using your apple cookie cutter, cut out apple shapes from the dough.
• Place them on a cookie sheet lined with parchment paper and bake for 6-8 minutes at 180C or until just puffy and no longer glossy. You don't want any browning to happen.
• Allow the cookies to cool completely on a wire rack.
• Once the cookies have cooled, it's time to add the finishing touches. Using royal icing in red and green, decorate the poison apples. Create spooky faces, drips, or any other sinister designs you like.

For more specific instructions on how to make and use royal icing:

• In a clean mixing bowl, combine the powdered sugar and water. If you prefer, you can also add a touch of vanilla extract for flavour, though it's optional.
• Use a hand mixer or stand mixer with a whisk attachment to beat the mixture on low speed initially to avoid creating a powdered sugar cloud. Gradually increase the speed to medium-high and beat until the icing reaches stiff peaks. This process may take about 5-7 minutes.
• Divide the royal icing into separate bowls based on the number of colours you intend to use for decorating your cookies. Add food colouring gels to each bowl and mix well until you achieve your desired shades.
• To outline your cookies, you'll want a thicker icing. If needed, add a bit more powdered sugar to thicken the icing. For flooding or filling in larger areas, you can thin the icing by adding small amounts of water, one teaspoon at a time, and stirring until you reach the desired consistency. The right consistency for outlining and flooding is crucial to creating clean, defined designs.
• Using a piping bag or a small zip-top bag with a tiny corner snipped off, fill it with the thicker, outlined icing. Outline the shape of your poison apple cookies with your chosen colour, such as red or green in the case of the poison apple cookies.
• After outlining, switch to the thinner, flooding icing to fill in the outlined areas. Allow the icing to flow evenly and smoothly. You can use a toothpick or icing tool to help distribute the icing and fill in any gaps.
• Allow the cookies to dry for several hours or overnight. The drying time depends on the thickness of the icing and the humidity of your environment. Ensure the icing is fully set before continuing to decorate, stacking or storing the cookies.