Preheat oven to 175°Celsius. Line baking trays with parchment paper.
Measure butter and sugar into a large mixing bowl. Beat on medium speed until the mixture turns creamy. Scrape the sides of the bowl.
Add the egg and beat again until all traces of the egg are no longer visible. Beat in the golden syrup.
Sift the flour, ground ginger, ground cinnamon, ground cloves, baking soda, and salt. Add these dry ingredients into the creamed wet ingredients.
Mix to form a dough ball. The dough will be sticky at this stage. For easy handling, divide the dough into smaller sections, wrap with plastic wrap and refrigerate for 10 minutes.
Place the chilled dough between 2 parchment sheets (or plastic sheets) and roll with 2 dowel rods on either side (see Note 1).
Cut with gingerbread man cookie cutter. Dip the cutter in flour to prevent sticking.
Transfer the cookies onto prepared baking trays. Use a flat rubber spatula to lift the cookies to keep their shape.
Bake for 6 minutes for soft and chewy cookies. Increase the baking time to 8 minutes for crispy gingerbread cookies (see Note 2).
Remove cookies from oven and rest in the tray for a few minutes before transferring onto a wire rack to cool completely. Store in an airtight container until ready to be decorated (see Note 3).
To make the royal icing, place the egg whites in a large, grease-free bowl. Whip on medium speed until they turn frothy and increase in volume. Gradually add the powdered sugar and continue beating until the icing turns smooth and gloss and stiff peaks form.
Add the lemon juice and mix again.
Divide the icing into 6 small bowls. Tint each bowl of icing in all the colors that are needed - black, brown, electric blue, electric green, pink and yellow.
Add a few drops of warm water to the bowls of blue, green and pink icing to dilute to a runny consistency. Mix well (see Note 4).
Fill the yellow icing into a piping bag fitted with tip 101. For the rest of the colors, fill them into piping bags without any tips.
To decorate the gingerbread boys, snip the tip of the black icing bag and pipe the hair in curly motion. Using the same icing, pipe 2 dots on the face for the eyes.
Snip the tip of the brown icing bag and pipe the nose and mouth.
For the shirt, snip the tip of the green icing bag and pipe the outline. Fill the outline with the same icing color. For the shorts, pipe the outline in blue and fill it with the same icing.
For the final touch, add two dots of black icing for the buttons on the shirt. Set the cookies aside to allow the royal icing to set completely before storing.
To decorate the gingerbread girls, use the black icing to pipe the outline for the hair. Fill the outline with piped lines to create hair strands.
Using the same black icing, pipe 2 dots for the eyes. For the nose and mouth, use the same brown as used for the gingerbread boys.
For the blouse, snip the tip of the pink icing bag and pipe the outline. Fill the outline with the same icing.
To make the frilly skirt, pipe 3 layers of frills starting from the bottom using yellow icing fitted with tip 101. The icing should be of stiff consistency to hold the shape of the frills.
Let the icing set completely before storing the cookies.