Whisk the dry ingredients. In a bowl, whisk flour, cornstarch, baking powder, and salt.
Set aside. This ensures even leavening and no clumps.
Cream butter and sugar. In a large bowl, beat butter and sugar on medium speed for 2–3 minutes until light and fluffy. Don’t rush this step; it builds structure and better texture.
Add egg, yolk, and extracts. Mix in the egg and egg yolk until smooth, then add vanilla and almond extract.
Scrape the bowl so everything blends evenly.
Add dry ingredients. On low speed, add the dry mixture in two additions. Mix just until combined. If the dough looks a bit crumbly, add up to 2 tablespoons milk, 1 teaspoon at a time, until it comes together.
Divide and chill. Split the dough in half, flatten into disks, and wrap.
Chill for at least 1 hour and up to 2 days. Chilling prevents spreading and makes rolling easier.
Roll and cut. Preheat oven to 350°F (175°C). Line baking sheets with parchment. On a lightly floured surface, roll dough to 1/4 inch thickness for soft centers, or 1/8 inch for crisper cookies.
Cut with holiday cutters and place on prepared sheets about 2 inches apart.
Freeze briefly. For the sharpest edges, pop the cut shapes into the freezer for 10 minutes before baking. This step keeps the details intact.
Bake. Bake 8–11 minutes, depending on thickness. The edges should look set with only the faintest gold. Do not overbake if you want soft cookies.
Cool. Let cookies rest on the sheet for 5 minutes, then transfer to a rack to cool completely before decorating.
Decorate. Use royal icing for a glossy, hard set that’s stackable, or buttercream for a softer, richer finish.
Add sprinkles before the icing sets.