With a stand mixer or hand mixer, cream together butter and sugars until blended. Mix in vanilla, cinnamon, egg, and mashed banana.
Slowly add flour to the butter/sugar mixture until incorporated. Then, gently stir in chocolate chips until just blended.
Scoop about 3 tbsp of cookie dough per cookie onto a baking pan lined with a silicone mat or parchment paper.
Bake at 350 degrees for 22-24 minutes, until the tops of the cookies start to turn golden brown.