Preheat your oven to 350°F and line 2 baking sheets with parchment paper and set aside.
In large bowl whisk your flour, salt and baking soda and set aside.
With your mixer or hand held mix butter and both sugars for about 5 mins. on med-high speed,
Add your egg and vanilla and mix for another 2 mins. Then add in your mashed banana.
With mixer on low add in your bowl of dry ingredients until just combined.
Fold in your walnuts and chocolate chips.
With a scoop or spoon scoop out 2-3 tbsps. of dough and place on prepared baking sheets. I used a large 3 tbsp. cookie scoop.
Bake in oven for 8-10 mins until nice golden edge and still a little gooey in the middle. Remember they continue to bake as they cool so you don't want to leave them in there longer then 10 mins.
Let them cool on baking sheet for about 5 mins before transferring to cooling rack. At this point you can top them with extra chocolate chips if you like.
Let them cool on rack for another 10-15 mins. ( if you can wait that long) before enjoying.