Preheat the oven to 350 degrees Fahrenheit. Line a baking sheet or two with parchment paper or nonstick liners.
Add the butter, brown sugar, and granulated sugar to a large bowl, or the bowl of a stand mixer, and mix until it is fluffy, and lightens in color, about 2 to 3 minutes. 1 cup unsalted butter, 1 cup brown sugar, 1/2 cup granulated sugar
Add in the eggs, and vanilla extract and mix them together until just combined. 2 large eggs, 1/2 TBS vanilla extract
Add the flour, baking soda, cinnamon, and salt to a medium bowl, and whisk them together. 1 3/4 cups all purpose flour, 1 tsp baking soda , 1/2 tsp salt, 1/2 tsp ground cinnamon
Slowly add the dry ingredients to the wet ingredients, and and stir them together until just combined.
Add the oats, toffee bits, and chocolate chips, and slowly fold them into the mixture with a rubber spatula. 3 cups old fashioned oats, 1 1/2 cups toffee bits, 1 cup chocolate chips
Scoop the dough into 2 TBS sized portions and roll into balls. Place them 2 to 3 inches apart on the prepared baking pan.
Bake the cookies for 9 to 12 minutes, or until the edges are golden and the centers look almost set.
Remove the pan from the oven and let the cookies cool for 5 minutes on the cookie sheet. Then transfer them to cool completely on a wire cooling rack.