📖 Instructions

1. Before you begin anything else, make sure your butter is softened to room temperature. This is really, really important for a smooth dough! If it's too cold, it won't cream properly, and if it's melted, your cookies might spread too much. Preheat your oven to 175°C (350°F) and line two large baking sheets with parchment paper or silicone mats. This ensures your cookies don't stick and cook evenly.
2. In a large mixing bowl, using an electric mixer (either a stand mixer with a paddle attachment or a hand mixer), cream together the softened unsalted butter and granulated sugar on medium speed. Beat them until the mixture is light, fluffy, and pale in color, which usually takes about 3-5 minutes. This step incorporates air, making your cookies tender.
3. Add the egg yolk and vanilla extract to the creamed butter mixture. Continue to beat on medium speed until these ingredients are fully combined. Don't worry if it looks a little curdled at first; keep mixing, and it will smooth out.
4. In a separate, medium-sized bowl, whisk together the all-purpose flour, cornstarch, and a pinch of salt. The cornstarch is our secret ingredient here; it helps make the cookies extra tender and gives them that delicate, melt-in-your-mouth texture. Gradually add this dry ingredient mixture to the wet ingredients in the large bowl, mixing on low speed until *just* combined. Be very careful not to overmix, as overmixing can lead to tough cookies!
5. Gather the dough into a ball and divide it in half. Gently flatten each half into a disc. Wrap each disc tightly in plastic wrap and refrigerate for at least 30 minutes. Chilling the dough helps prevent spreading during baking and makes it much easier to roll out.
6. Once the dough is chilled, remove one disc from the refrigerator. Lightly flour your work surface and a rolling pin. Roll out the dough to about 1/4 inch (6mm) thickness. If the dough gets too sticky or warm, pop it back in the fridge for a few minutes.
7. Using your favorite cookie cutters, cut out shapes from the rolled dough. Carefully transfer the cut-out cookies to your prepared baking sheets, leaving about an inch between each cookie. Re-roll any dough scraps and cut out more shapes until all the dough is used.
8. Bake the cookies in your preheated oven for 10-12 minutes, or until the edges are very lightly golden. The centers should still be pale. Baking time can vary, so keep an eye on them! Do not overbake, as this will make them dry and less tender.
9. Once baked, allow the cookies to cool on the baking sheets for about 5 minutes before carefully transferring them to a wire rack to cool completely. They must be entirely cool before you even *think* about painting them; otherwise, your edible paint will melt or smudge.
10. While the cookies are cooling, prepare your edible paints. You can use gel food coloring diluted with a tiny bit of clear vanilla extract or vodka (the alcohol evaporates quickly). Start with a few drops of color and add liquid sparingly until you reach your desired consistency—like watercolor paint. For solid colors, you might use straight gel food coloring or edible food paints available in tubes.
11. Now for the fun part: painting! Using clean, small food-safe paint brushes (you can get these specifically for baking or use new, clean art brushes), start decorating your cooled cookies. You can create intricate patterns, simple dots, stripes, or even tiny scenes. Let your imagination run wild! If you want to create different layers of color, allow each layer to dry before applying the next.
12. Once painted, let the cookies sit at room temperature for at least 15-30 minutes, or until the edible paint is completely dry to the touch. This prevents smudging. Once dry, store your beautiful, artistic butter cookies in an airtight container at room temperature. They're perfect for gifting, parties, or simply enjoying with a cup of tea. Enjoy your edible masterpieces!