Measure out all ingredients and ensure butter and eggs are at room temperature (about 70°F), as this helps create a lighter, more uniformly mixed dough. Whisk together the flour, salt, baking powder, and baking soda in a medium bowl and set aside. Room temperature ingredients are crucial for proper emulsification and will give you better texture in the final cookies.

In a large bowl, beat the softened butter and sugar together on medium-high speed for 3-4 minutes until the mixture is pale, fluffy, and noticeably lighter in color. This creaming process incorporates air into the dough, which helps create a tender crumb and proper rise during baking. Scrape down the bowl occasionally to ensure even mixing.

Add eggs one at a time to the creamed butter and sugar from Step 2, beating well after each addition until fully incorporated before adding the next. Add vanilla extract and mix for about 30 seconds, then add milk and mix until smooth and cohesive. The mixture should look creamy and slightly emulsified at this point.

Reduce mixer speed to low and add the dry ingredient mixture from Step 1 to the wet mixture from Step 3 in three additions (about 2 cups at a time), mixing on low speed until just combined after each addition. Do not overmix—stop as soon as you don't see streaks of flour. Overmixing develops gluten and creates tough cookies instead of tender ones. I like to finish the last bit of mixing with a spatula by hand to avoid overworking the dough.

Cover the dough with plastic wrap and refrigerate for at least 2 hours, or preferably overnight. Chilling relaxes the gluten and allows the flavors to meld, which improves both texture and taste. The dough will be much easier to handle and will spread less during baking when it's properly chilled.

Preheat your oven to 350°F. Scoop chilled dough into 1-inch balls and place them on parchment-lined baking sheets about 2 inches apart. Dip the bottom of a glass into sugar and use it to gently flatten each ball into a disk about ¼-inch thick. Bake for 12 minutes or until the edges are light golden and the centers still look just barely set—they will continue to cook slightly from residual heat. I find that slightly underbaking keeps them tender; they'll seem soft when warm but will firm up as they cool.

Let the baked cookies sit on the baking sheet for 3 minutes to set slightly, then transfer them to a wire cooling rack. Allow them to cool completely before serving or storing. This resting period on the sheet prevents them from breaking apart while they're still fragile, and the wire rack ensures even cooling on all sides.