1. Preheat oven to 350°.
2. Weigh or lightly spoon flour into dry measuring cups; level with a knife. Combine flour, oats, baking soda, and salt in a medium bowl; stir with a whisk. Place sugar and butter in a large bowl; beat with a mixer at medium speed until well blended (about 5 minutes). Add vanilla and egg; beat well. Add flour mixture; beat just until combined. Stir in toffee bits.
3. Drop dough by tablespoonfuls 2 inches apart on 2 baking sheets coated with cooking spray. Bake at 350° for 11 minutes or until lightly browned. Cool on pans 1 minute. Remove cookies from pans; cool completely on wire racks.