Ingredients Con't:
8 ounces semisweet chocolate, coarsely chopped into 1/4 inch chunks
1/2 cup coarsely chopped walnuts (about 2 ounces), toasted (optional)

1. Preheat oven to 375 degrees. Whisk together flours, salt, and baking soda in a small bowl; set aside. Put butter and sugars into the bowl of an electric mixer fitted with the paddle attachment; mix on medium speed until pale and fluffy. Reduce speed to low. Add egg and vanilla; mix until combined. Mix in banan. Add flour mixture; mix until just combined. Stir in oats, chocolate chunks, and walnuts.

2. Using a 1 1/2 inch ice cream scoop, drop dough onto baking sheets lined with parchment paper, spacing about 2 inches apart. Bake cookies, rotating sheets halfway through, until golden brown and just set, 12 to 13 minutes. Let cool on sheets on wire racks 5 minutes. Transfer cookies to wire racks; let cool completely. Cookies can be stored in airtight containers up to 2 days.