- Heat oven to 350°F.
- Combine flour, powdered sugar, cocoa and baking soda in medium bowl; cut in butter until mixture is crumbly.
- Press into bottom of ungreased 13x9x2-inch baking pan.
- Bake 15 minutes.
- Beat cream cheese until fluffy.
- Add sweetened condensed milk, eggs and vanilla; beat until smooth.
- Stir in 1 cup toffee bits.
- Pour mixture over hot crust.
- Bake 20 to 25 minutes or until set and edges just begin to brown.
- Remove from oven.
- Cool 15 minutes.
- Sprinkle remaining ¾ cup toffee bits evenly over top.
- Cool completely.
- Refrigerate several hours or until cold.
- Cover; store leftover bars in refrigerate.