📖 Instructions

1. Before you even touch a measuring spoon, take your butter out. Seriously! It needs to be nice and soft, almost like it's been sitting at room temperature for an hour or two. This is key for that creamy texture. Also, preheat your oven to 375°F (190°C) and line your baking sheets with parchment paper. This parchment paper is your secret weapon against sticking and makes cleanup a breeze.
2. In a large bowl, or the bowl of your stand mixer, cream together the softened unsalted butter and granulated sugar. Do this on medium speed until the mixture is light, fluffy, and looks almost pale yellow. This usually takes a good 3 to 5 minutes. Make sure to scrape down the sides of the bowl with a spatula often to get everything incorporated.
3. Now, add in the egg and vanilla extract. Beat on medium speed until everything is just combined. Be careful not to overmix here; we're just aiming for smooth, not trying to make a soufflé!
4. In a separate, medium-sized bowl, whisk together your all-purpose flour, baking powder, and salt. Whisking ensures these dry ingredients are evenly distributed, which helps with a consistent cookie texture.
5. Gradually add the dry ingredients to the wet ingredients. Do this about a third at a time, mixing on low speed until *just* combined after each addition. The moment you no longer see streaks of flour, stop mixing! Overmixing at this stage can lead to tough cookies, and we want soft ones, right?
6. The dough should be soft, maybe even a little sticky, but it shouldn't be too wet. If it feels too wet, add another tablespoon of flour. Don't worry about chilling this dough; that’s another secret to their softness! Grab small portions of dough, about 1 tablespoon each, and roll them into smooth balls. Place these balls about 2 inches apart on your prepared baking sheets.
7. For that classic sugar cookie look (and to help them spread just right), gently flatten each dough ball. You can use the bottom of a glass dipped in sugar, or your palm. Don't press too hard, just enough to slightly flatten them.
8. Bake the cookies one sheet at a time in your preheated oven for 8 to 10 minutes. Watch them carefully! The edges should be just set and very lightly golden, but the centers should still look soft and perhaps even a little underbaked. This is crucial for that 'melt-in-your-mouth' quality. Overbaking is the enemy of a soft sugar cookie.
9. As soon as you pull the cookies from the oven, let them sit on the baking sheet for about 5 minutes. They’ll continue to set up a bit as they cool. After 5 minutes, carefully transfer them to a wire rack to cool completely. If you want to glaze them, wait until they are totally cool.
10. If you're making a simple glaze, whisk together 1 cup of powdered sugar with 2-3 tablespoons of milk (or water) and 1/2 teaspoon of vanilla extract until smooth. Drizzle or spread over cooled cookies. Enjoy your tender, buttery, melt-in-your-mouth masterpieces!