Preheat oven to 375 degrees.
Mix together flour, salt, baking powder, baking soda and set aside.
Beat butter and sugar with an electric mixer until creamy. Beat in the eggs, one by one, then stir in the sour cream and vanilla.
Add flour mixture in 3 parts, stirring well after each addition. Stir in chocolate chips.
Drop by tablespoons (or use a cookie scoop) onto parchment lined baking sheets. Bake cookies for 12-15 minutes or until just set and edges are lightly browned. Alternatively, you can scoop the cookie dough onto parchment lined plates, cover with plastic and chill overnight before baking as directed above.
Let cool on baking sheets for about 5 minutes then transfer to a wire rack and let cool completely.