Preheat the oven to 350 degrees F. Grease a parchment-paper-lined baking sheet.
In a stand mixer fitted with the paddle attachment, add the butter, sugar and vanilla. Beat on medium speed until light and fluffy. Add the eggs, one at a time, scraping down the sides of the bowl after each addition. Add the sour cream, and mix on low speed until incorporated.
In a medium mixing bowl, sift together the flour, baking soda and salt. Add the dry ingredients to the wet ingredients, and mix on low speed until just combined to avoid over-mixing. Scoop the dough onto the prepared baking sheet, about 20 large cookies. Bake until the edges are golden, 10 minutes.