Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper.
In a medium bowl, whisk together the all-purpose flour, baking soda, baking powder, and salt. Set aside.
In a large bowl, beat the softened unsalted butter and granulated sugar together with an electric mixer on medium speed until light and fluffy, about 3 minutes.
Add the egg and vanilla extract to the butter mixture and beat until fully combined.
Mix in the sour cream until smooth.
Gradually add the dry ingredients to the wet ingredients, mixing on low speed until just combined and a dough forms.
Turn the dough out onto a lightly floured surface and shape it into a log approximately 12 inches long and 2 inches in diameter.
Wrap the dough log tightly in plastic wrap and refrigerate for at least 1 hour until firm.
Remove the chilled dough log from the refrigerator and unwrap it.
Using a sharp knife, slice the log into 1/4-inch thick rounds and place them about 2 inches apart on the prepared baking sheet.
Bake in the preheated oven for 10 to 12 minutes, or until the edges are lightly golden.
Remove from the oven and allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.