Sift the dry ingredients: Put a sieve over a large bowl. Add 1 cup all-purpose flour, 1/8 tsp salt, and 1/8 tsp baking soda. Sift them into the bowl.

Beat the butter: In a clean bowl, add 2 oz unsalted butter and 2 tbsp sugar. Beat with an electric mixer until the butter turns pale.

Beat egg and butter: Add 2 egg yolk, 1 egg white, and 1/2 tsp vanilla extract to the butter mixture. Continue beating until fully incorporated.

Add the dry ingredients to the butter mixture: Divide the flour mixture into three parts. Gradually add it to the egg and butter mixture. Beat it with the electric mixer. Once the batter starts to clump into pieces of dough, switch to a spatula.

Form the dough: Turn the dough onto a clean work surface. Gather the crumbs and form into a roughly round dough ball. Wrap in cling film and refrigerate for 30 minutes.

Put parchment paper over the dough: Put a large piece of parchment paper on the work surface and sprinkle flour on it. Place the dough on the paper and sprinkle more flour on the dough. Then, place another piece of parchment paper on top of the dough. These layers of paper will allow you to roll and remove the cut-out cookies with ease later.

Roll the dough: Using a rolling pin, press the dough gently before rolling it 0.2-inch thick.

Cut out the cookies: Using a cookie cutter, cut the cookies into desired shapes. Carefully remove excess dough around the cookies and transfer them to a lined baking sheet using an offset spatula. Gather the scraps and form into a dough ball. Continue rolling and cutting until there is no scrap left.

Freeze the cookies: Put the cookie tray in the freezer for 5 minutes before baking. While you wait, preheat the oven to 325°F.

Bake the cookies: Put the cookie tray in the middle of the oven and bake for 15 minutes. Once baked, remove the cookies from the oven and let them cool completely. While you wait, make the icing.

Beat the egg white and powdered sugar: In a clean bowl, add the remaining 1 cold egg white, 3/4 tsp lemon juice, and 1/2 cup powdered sugar. Using an electric mixer, beat for about 7 minutes or until stiff peaks form.

Add color to the icing: Divide the icing into small bowls. Add food coloring to each bowl and stir with a clean spoon to get the desired colors.

Decorate: Pour the colored icing into piping bags. Cut off a small part of the tip and start decorating.

Allow the icing to dry for several hours before serving.