In a medium bowl, whisk together the flour, baking soda, and baking powder until evenly combined.
In a large bowl, cream the softened butter and sugar on medium speed until light and fluffy, about 2–3 minutes.
Beat in the egg and vanilla extract until fully incorporated.
Gradually add the dry ingredients to the wet mixture, mixing on low speed until a soft dough forms.
Drop rounded teaspoonfuls of dough onto ungreased baking sheets, spacing 2 inches apart.
Bake for 8–10 minutes, until the edges are lightly golden and the centers are set.
Let cookies cool on the pan for 5 minutes, then transfer to a wire rack to cool completely.
Notes
Ensure butter and egg are fully at room temperature before creaming for optimal texture.If cookies spread too much, chill dough for 10 minutes before baking.Store cooled cookies in an airtight container at room temperature for up to 3 days to maintain softness.