In a bowl, combine softened unsalted butter and icing sugar. Whisk until combine and smooth.
Add egg, half portion at a time, to the mixture. Whisk until combine before adding more.
Sift all-purpose flour and corn starch (you can also sub with 90g cake flour instead) into the mixture. Mix until a dough is formed.
Place the dough onto parchment paper. Roll it into a 3mm thick rectangle. The width is similar to the height of an actual matchstick (approx 4-5cm). Put it in the freezer for 30 minutes.
Preheat the oven to 311°F (155°C). Line the baking sheet with parchment paper or a silicone baking mat.
Boil water in a saucepan. Set aside.
Remove the dough from the freezer. Use a sharp knife and cut the dough into small rectangles, just like a matchstick. Place them carefully onto the lined baking sheet.
Bake for 12-15 minutes. These cookies won't change color so you can flip over the cookie carefully to see if it is fully cooked.
While the cookies are baking, prepare the chocolate dipping sauce. In a medium mixing bowl, add semi-sweet (or dark) chocolate chips. If you are using chocolate blocks, make sure to chop beforehand. This allows the chocolate to melt easily.
Melt the chocolate in a double boiler by placing the heat-resistant bowl on top of the saucepan (hot water). Stir often and watch it melt. Remove bowl from the heat once the chocolate is melted to prevent burning.
Once the cookies are baked, transfer them to a cooling tray. Let it cool for 5 minutes.
Dip one side of the cookies into the chocolate to create the "match head". Allow the chocolate to solidify. You can place it in the freezer for 5 minutes. Ready to serve.