Preheat oven to 300 degrees F. Spray an 8x8 baking pan with cooking spray.
With an electric mixer, blend the sugar and butter until creamy. Add egg and vanilla and beat at medium speed until light and smooth. Scrape down sides of the bowl, then add the flour and baking soda. Blend at low speed until almost combined. Add the chocolate chips and finish combining on low. Do not overmix!
Transfer batter into pan and smooth top to make it even. Place pan in middle of the oven and bake for 35 to 45 minutes or until toothpick comes out clean but center is still soft. Cool on rack. When cooled, use a sharp knife to cut into small bars. ENJOY!!