Beat butter and sugar in a large bowl until light and fluffy. Add egg and vanilla and beat to combine.

Whisk together flour and baking soda. Add to butter/sugar mixture alternately with sour cream, beginning and ending with flour, beating until just combined.

Stir in chocolate chips. Dough will be somewhat crumbly.

Divide dough in half. Firmly press and shape each half into a log 2 inches in diameter.

Wrap logs in parchment or wax paper. Chill at least 4 hours or overnight.

Preheat oven to 375°F. Line baking sheets with parchment paper or non-stick liners.

Unwrap roll and cut into 1/4-inch thick slices. Place slices on baking sheets 1 inch apart.

Bake for 9 to 11 minutes, until edges have slightly browned. Cool cookies on baking sheet for 1 minute.

Transfer cookies to a wire rack and cool completely. Repeat with remaining dough.