📖 Instructions

1. Begin by creaming together the softened unsalted butter and granulated sugar in a large mixing bowl. Use an electric mixer on medium speed for about 3-5 minutes, until the mixture is light, fluffy, and a pale yellow. This step is super important for the texture of your cookies, so don't rush it!
2. Next, beat in the egg yolk and vanilla extract. Continue mixing until everything is well combined, scraping down the sides of the bowl with a rubber spatula as needed to ensure no streaks of butter remain.
3. In a separate bowl, whisk together the all-purpose flour, cornstarch, and a pinch of salt. The cornstarch is our secret ingredient here; it helps make these cookies extra tender and gives them that melt-in-your-mouth quality.
4. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix the dough, as this can make your cookies tough. The dough should come together and be soft but not sticky.
5. Divide the dough in half, flatten each half into a disc, and wrap them tightly in plastic wrap. Refrigerate for at least 30 minutes, or up to 2 hours. Chilling the dough prevents the cookies from spreading too much during baking, ensuring they hold their crisp, delicate shapes.
6. Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper or silicone baking mats. This makes for easy cleanup and prevents sticking.
7. On a lightly floured surface, roll out one disc of chilled dough to about 1/4 inch thickness. Use your favorite cookie cutters to cut out shapes. Gather any scraps, gently re-roll them, and cut out more cookies until all the dough is used. Try not to overwork the scraps!
8. Carefully transfer the cut-out cookies to the prepared baking sheets, leaving about an inch between each one. If the cookies feel too soft, pop the baking sheets into the fridge for 10 minutes before baking to firm them up again.
9. Bake for 10-12 minutes, or until the edges are just barely golden. The centers should still look pale. Keep a close eye on them because butter cookies can go from perfectly baked to overdone quite quickly. Remember, every oven is a little different!
10. Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely. They must be entirely cool before you even think about painting them. Warm cookies will just make your 'paint' run, and no one wants that mess.
11. Now for the fun part: preparing your edible paint! Squeeze a small amount of your chosen gel food coloring into separate small dishes or a painter's palette. Add just a few drops of clear vanilla extract (or lemon extract, or even vodka for faster drying) to each color and mix with a clean small brush or toothpick until you reach your desired consistency. You want it thin enough to paint smoothly, but not so thin that it's watery.
12. Using small, clean food-safe paint brushes, begin to paint your designs onto the completely cooled butter cookies. You can create flowers, dots, stripes, abstract patterns, or whatever your creative heart desires. Layer colors once the first layer is dry for more depth. This is where your inner artist shines!
13. Allow the painted cookies to dry completely before stacking or storing them. This usually takes about 15-30 minutes, depending on how much 'paint' you used. Enjoy your beautiful, edible works of art!
14. To make clean up a breeze, make sure to wash your brushes immediately after using them with warm, soapy water. This helps to keep them in good condition for your next cookie painting adventure.