Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

Either in a stand mixer with a paddle attachment, or in a large bowl with a hand mixer, cream the vegan butter, cornstarch, and sugar together until mostly smooth and fluffy.

Add the plant-based milk, vanilla extract, and other extracts if you are using them. Mix for another 90 seconds, until fully combined.

In a separate bowl, sift, or whisk together the flour, baking powder, baking soda, and salt. Gradually add the dry ingredients to the wet mixture, mixing until a soft dough forms.

Optionally, for neater cookies that don’t spread as much, chill the dough in a sealed container for at least 30 minutes before rolling it.

On a clean, lightly floured surface, roll the dough out to ⅛" (3 mm.) for thinner, crispier cookies, or ¼" (6 mm.) for thicker, softer cookies. Sprinkle flour lightly over the top of the dough and on your rolling pin to prevent sticking.

Use cookie cutters to create shapes. Re-roll and cut the scraps to use up all of the dough.

Transfer the cookies to the prepared baking sheet, leaving a 1 inch (2.5 cm) gap between them.

Bake for 11-14 minutes (depending on the size and thickness of your cookies) at 350°F (175°C), or until the edges are just starting to turn golden.

Allow the cookies to cool on the baking sheet for a few minutes, then transfer them to a wire rack to cool completely.

Once the cookies are fully cooled, decorate them with your prepared royal icing, or vegan buttercream.