📖 Instructions

1. Before you even think about mixing anything, ensure your butter is at room temperature. This is crucial for creaming it properly and achieving that smooth, consistent dough. If it's too cold, your cookies will be dense; too warm, and they'll spread too much. Take it out an hour or two before you start. Also, preheat your oven to 375°F (190°C). Line two large baking sheets with parchment paper or silicone baking mats. This prevents sticking and helps with even baking.
2. Now for the crumb topping: In a medium bowl, combine 1/2 cup (113g) cold unsalted butter, diced into small cubes, with 1 cup (120g) all-purpose flour, 1/2 cup (100g) granulated sugar, 1/4 teaspoon ground cinnamon (optional, but lovely!), and 1 teaspoon vanilla extract. Using your fingertips or a pastry blender, work the butter into the dry ingredients until coarse crumbs form. You want some pea-sized pieces, not a smooth paste. Don't overmix! Place this bowl in the refrigerator while you make the cookie dough.
3. Next, the cookie dough: In a large bowl, using an electric mixer (stand mixer with paddle attachment or a hand mixer will work wonders here), cream together 1 cup (226g) softened unsalted butter and 1 1/2 cups (300g) granulated sugar on medium-high speed until the mixture is light, fluffy, and pale in color. This usually takes about 3-5 minutes. Don't rush this step, it incorporates air into your dough, making the cookies tender.
4. Reduce the mixer speed to low. Beat in 2 large eggs, one at a time, mixing well after each addition. Scrape down the sides of the bowl with a rubber spatula to ensure everything is fully combined. Then, stir in 2 teaspoons of pure vanilla extract. The mixture might look a little curdled at this point, but don't worry, it'll come together.
5. In a separate medium bowl, whisk together 3 cups (360g) all-purpose flour, 1 teaspoon baking soda, 1/2 teaspoon baking powder, and 1/2 teaspoon salt. Make sure these dry ingredients are thoroughly combined to ensure your leavening agents are evenly distributed.
6. Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix the dough! Overmixing develops too much gluten, which can lead to tough cookies. As soon as you see no more streaks of flour, stop the mixer. The dough will be soft, but not sticky.
7. Roll the dough: Scoop out tablespoon-sized portions of dough and roll them into smooth balls between your palms. The size doesn't need to be precise, but try to keep them consistent for even baking. Place these dough balls about 2 inches apart on your prepared baking sheets. Don't flatten them.
8. Now for that delightful crumb! Take your chilled crumb topping out of the fridge. Gently press about 1-2 teaspoons of the vanilla crumb mixture onto the top of each cookie dough ball. Don't be shy; a good amount of crumb is what makes these special. Lightly press it in so it adheres to the dough.
9. Bake for 9-11 minutes, or until the edges are lightly golden and the centers are set but still look soft. The key to a soft sugar cookie is not to overbake them! The crumb topping should also look nicely toasted. If you prefer a chewier cookie, lean towards the shorter baking time. For a firmer cookie, bake a little longer.
10. Once baked, remove the baking sheets from the oven. Let the cookies cool on the sheets for about 5 minutes before carefully transferring them to a wire rack to cool completely. This prevents them from breaking and allows them to set up properly. If you can resist eating them all immediately, they store well in an airtight container at room temperature for up to 3-4 days. Enjoy every single crumbly bite!
11. Optional: If you're feeling extra fancy and want to amp up the vanilla flavor even more, you can lightly dust the cooled cookies with a sprinkle of powdered sugar just before serving. It adds a lovely finish and a tiny extra touch of sweetness!