Preheat oven to 350°F. Line 2 baking sheets with parchment paper. Set aside.
In the bowl of a stand mixer, cream together 8 tablespoons unsalted butter, 6 tablespoons brown sugar, ¼ cup granulated sugar until well incorporated.
Add 1 egg, 1 medium banana and ½ teaspoon vanilla extract and beat until smooth.
In a medium bowl, combine 1 cup + 1 tablespoon all-purpose flour, ½ teaspoon baking soda, ¼ teaspoon cinnamon, ¼ teaspoon sea salt, and 1½ cups rolled oats.
Add dry mixture to wet and mix until just incorporated. Mix in ½ cup toffee bits . (And mini-chips if desired.)
Bake on a non-stick cookie sheet for approximately 12 minutes or until the edges just begin to brown.
When baked through, remove from oven and allow to set on the cookie sheet for about 5 minutes before transferring to a cooling rack.