Start by clearing a bit of counter space and laying down some parchment paper. Preheat your oven to 325°F (160°C) so it’s ready when your dough is set.

In a large bowl, toss in your salted butter and granulated sugar, then beat them together until the mixture is light, fluffy, and creamy. Make sure to scrape the sides a couple of times so nothing gets left behind, this little step makes the dough soft and perfect for rolling.

Lower your mixer speed, add the egg and vanilla extract, and blend until everything comes together smoothly.

In a separate bowl, whisk the all-purpose flour, cornstarch, baking powder, and baking soda. Slowly add this dry mix to your wet ingredients, a little at a time, keeping the mixer low so the dough stays tender. If it looks crumbly, don’t stress, just knead gently with your hands until it forms a soft, workable ball.

Lightly flour your work surface and roll out the dough to roughly ¼ inch thick. A slightly soft dough makes for tender cookies, so don’t over-flour or over-roll. You can roll from the center out and give the dough a quarter turn every so often to prevent sticking.

Use your cookie cutter to press out festive shapes, pressing straight down without twisting to keep the edges neat. If the dough clings to the cutter, dust it lightly with flour rather than adding more to the dough.

Transfer each cookie carefully to a baking sheet using a thin spatula, supporting the edges with your fingers so they keep their shape.

Bake the cookies for about 12–13 minutes. The edges should be set while the centers remain soft. Smaller cookies may need just a touch less time, so peek at them closely. Let them sit on the sheet for a few minutes before moving to a cooling rack, this helps avoid cracking and keeps them looking perfect.

While the cookies cool, whip up the frosting by combining powdered sugar, salted butter, milk, and vanilla extract until smooth and creamy. Gradually mix in green food coloring until you get that festive shade you love.

Spoon the frosting into a piping bag with a star tip and start decorating! Pipe tiny stars, swirls, or dots, piping in short bursts usually gives the nicest results. Sprinkle on edible stars or glitter if you like; it really makes the trees shine. Enjoy!