1. Heat oven to 350°F. Grease 13x9x2-inch baking pan.
2. Beat butter and brown sugar in large bowl until well blended. Add eggs and vanilla; beat well.
3. Stir together flour, baking soda, cinnamon and salt. Gradually add to butter mixture, beating until blended. Set aside 1/4 cup toffee bits. Stir remaining toffee bits and oats into batter (batter will be stiff). Spread batter into prepared pan; sprinkle reserved 1/4 cup toffee bits over surface.
4. Bake 25 minutes or until wooden pick inserted in center comes out clean. Cool completely in pan on wire rack. Cut into bars. Makes 24 to 36 bars.