Preheat oven to 350°F (175°C)
Line baking sheets with parchment paper
Gather ingredients: flour, baking soda (or baking powder), salt, butter (softened), brown sugar, granulated sugar, eggs, vanilla extract, and chocolate chips (optional)
In a bowl, whisk together flour, baking soda, and salt
In a separate bowl, cream butter with brown sugar and granulated sugar until light and fluffy
Beat in eggs one at a time, then mix in vanilla
Gradually mix in dry ingredients until just combined
Fold in chocolate chips (or other mix-ins)
Scoop dough into 1 to 2 tablespoon portions and place on baking sheets
Leave space between cookies
Bake 9–12 minutes, until edges are lightly golden and centers look slightly underbaked
Cool on the baking sheet 5 minutes
Transfer to a wire rack to cool completely
Store airtight at room temperature for up to 3–5 days or freeze for longer