📖 Instructions

1. **Step 1: Prep Your Workspace and Ingredients** Begin by clearing your countertop and gathering all your ingredients. It’s a good practice to have everything at room temperature, especially the butter and eggs. This helps them combine smoothly, preventing a lumpy dough. Line two large baking sheets with parchment paper or silicone baking mats; this is crucial for preventing sticking and ensures even baking. If you skip this, your cookies might spread unevenly or stick to the pan, ruining those crisp edges.
2. **Step 2: Cream Butter and Sugar Until Light and Fluffy** In the bowl of a stand mixer fitted with the paddle attachment (or a large bowl with a handheld electric mixer), add the softened unsalted butter and granulated sugar. Beat on medium-high speed for about 3-4 minutes. You're looking for a mixture that's visibly lighter in color, pale yellow, and incredibly fluffy. This process incorporates air into the butter, which is vital for the cookies' soft texture and helps create those slightly crisp edges.
3. **Step 3: Add Eggs and Vanilla** Reduce the mixer speed to low. Add the large egg and the egg yolk, one at a time, mixing until each is just incorporated before adding the next. Overmixing here can develop too much gluten. Next, stir in the pure vanilla extract. Scrape down the sides of the bowl with a rubber spatula to ensure everything is fully combined. The mixture should still be smooth and creamy.
4. **Step 4: Whisk Dry Ingredients** In a separate medium bowl, whisk together the all-purpose flour, cornstarch, baking powder, and fine sea salt. The cornstarch is our secret weapon for those soft centers – it interferes with gluten development, keeping the cookies tender. Make sure there are no lumps in your dry mixture.
5. **Step 5: Gradually Add Dry to Wet Ingredients** With the mixer on low speed, slowly add the dry ingredient mixture to the wet ingredients, about a third at a time. Mix only until just combined. As soon as you see no more streaks of flour, stop the mixer. Overmixing at this stage will make your cookies tough, and nobody wants a tough sugar cookie. The dough will be soft and a bit sticky, but that’s okay!
6. **Step 6: Divide and Chill the Dough** Turn the dough out onto a lightly floured surface. Divide it into two equal portions. Gently form each portion into a disc, wrap tightly in plastic wrap, and refrigerate for at least 30 minutes. Chilling is absolutely non-negotiable for sugar cookies. It helps the butter firm up, preventing the cookies from spreading too much in the oven, and makes the dough much easier to roll and cut. Plus, it allows the flavors to meld beautifully. If you’re in a hurry, you can chill in the freezer for 15 minutes, but 30 in the fridge is ideal.
7. **Step 7: Preheat Oven and Prepare for Rolling** While the dough chills, preheat your oven to 375°F (190°C). If your oven runs hot, you might consider 350°F (175°C) to prevent over-browning. Take one disc of chilled dough from the fridge (keep the other chilled). Lightly flour your work surface and your rolling pin. Flour generously, but not excessively, to avoid drying out the dough.
8. **Step 8: Roll and Cut the Dough** Roll the dough out to about 1/4-inch thickness. For thicker, softer cookies, go slightly thicker. For thinner, crisper cookies, roll a bit thinner. Use your favorite cookie cutters to cut out shapes. Place the cut-out cookies on your prepared baking sheets, leaving about 1-2 inches between them. Gather the scraps, gently re-roll, and cut more cookies until all the dough is used. Try not to overwork the dough when re-rolling scraps; too much handling can make them tough.
9. **Step 9: Bake to Golden Perfection** Bake one sheet at a time in the preheated oven for 8-10 minutes. Baking time will vary based on your oven and the thickness of your cookies. You're looking for edges that are lightly golden brown, but the centers should still look soft and slightly pale. This is the sweet spot for that perfect soft-center, crisp-edge combination. Do not overbake, or you’ll lose the softness!
10. **Step 10: Cool and Enjoy!** Once baked, immediately transfer the cookies from the baking sheets to a wire cooling rack using a thin metal spatula. Let them cool completely. They will firm up as they cool. Resisting the urge to eat them warm is the hardest part, I know! But cooling allows their structure to set properly. Once cool, they’re ready for decorating, or simply enjoy them as is. They’re absolutely delicious plain, too!