Prep your workspace: Line two large baking sheets with parchment paper and set aside. You'll need these ready before baking.

Soften the butter: Let unsalted butter sit at room temperature for 30–60 minutes. It should be soft enough to easily press with your finger but still hold its shape.

Cream butter and sugar: Add softened butter and granulated white sugar to a large mixing bowl. Using an electric mixer on medium speed, beat for 3 minutes until the mixture is pale, fluffy, and doubled in volume. You'll see light streaks throughout and the texture will be airy.

Add egg and vanilla: Crack the large egg into the bowl and add vanilla extract. Beat on medium speed for 1–2 minutes until fully incorporated and the mixture is smooth. The bowl should smell fragrant and vanilla-forward.

Combine dry ingredients: In a separate bowl, sift together all-purpose flour and salt (sifting removes lumps and aerates the flour). Gradually add this flour mixture to the wet ingredients while mixing on low speed. Stop as soon as no white streaks of flour remain—this takes about 1–2 minutes. Checkpoint: You are ready to move on when the dough just comes together with no dry pockets of flour visible.

Chill the dough: Divide dough in half and wrap each portion tightly in plastic wrap. Refrigerate for 3 to 4 hours or overnight until firm. (If you're short on time, 2 hours works, but overnight chilling gives the best results.) The dough should be cold and firm enough to handle without sticking.

Preheat the oven: About 15–20 minutes before baking, preheat your oven to 350°F. Position your racks in the upper-middle and lower-middle positions so both baking sheets can fit comfortably.

Roll the dough: Remove one portion of chilled dough from the refrigerator. Lightly dust your work surface and a rolling pin with flour to prevent sticking. Gently roll dough to 1/4 inch thickness (about the thickness of a pencil). If dough cracks at the edges, let it warm up for 2–3 minutes. Checkpoint: You are ready to move on when your dough is even, 1/4 inch thick, and holds its shape when lifted.

Cut cookies: Using your favorite cookie cutters (flowers, hearts, or any shape), press firmly into the rolled dough and lift out each shape. Place cut cookies 1 inch apart on your prepared parchment-lined baking sheets. Re-roll scraps gently and cut additional cookies.

Bake: Place baking sheets on preheated 350°F oven racks. Bake for 6–8 minutes until edges are very lightly golden but centers still look pale. The cookies should not be dark brown—they'll continue cooking slightly as they cool. The baking time varies depending on your oven and cookie size; start checking at 6 minutes.

First cooling phase: Remove cookies from the oven and let them rest on the hot baking sheet for exactly 5 minutes. During this time they'll firm up and be easier to move without breaking.

Complete cooling: After 5 minutes, carefully transfer cookies to a wire cooling rack using a thin spatula. Let them cool completely at room temperature for 15–30 minutes until they're firm and no longer warm to the touch. Checkpoint: Cookies are ready to decorate when they are completely cool and feel sturdy when gently pressed.

Optional decorating: Once cooled completely, frost with royal icing, buttercream, or fondant. Add sprinkles, edible glitter, or hand-painted designs as desired.