Heat oven to 350°F and lightly grease cookie sheet or line with parchment paper.
With a standard mixer with a paddle attachment, beat butter and brown sugar on high speed until well combined.
Add eggs and vanilla on medium speed and mix until just combined.
Add flour, baking soda, cinnamon and salt on slow speed and beat until just blended
Stir in oats and 1 cups of toffee bits.
Use a medium Drop 1 1/2 inch balls of dough on cookie sheet about 2 inches apart. These cookies will spread.
Bake 10 to 12 minutes or until edges are lightly browned.
Immediately sprinkle on some of the leftover toffee bits.
Let cool for one minute on the baking sheet and then transfer to wire rack.