MAKE THE COOKIES:1. Preheat oven to 350F and line a baking sheet with parchment paper. Set aside.2. In a medium mixing bowl using electric hand mixer, combine cashew butter and sugar. You can use a whisk and do this by hand, but I find an electric mixer works best.3. Add in egg and vanilla if using, beat again. Then add salt and baking soda, beating together one last time. Fold in chocolate chips.4. Use rounded tablespoon to create cookie dough balls (about 1.5 TBS total) and place on prepared baking sheet about 2" part. Gently flatten dough slightly with palm of hand, re-shaping as necessary to keep circle shape.5. Bake cookies for 8-10 minutes. Careful not to over-bake, or cookies will be crumbly. Remove baking sheet from oven and allow cookies to cool on baking sheet for 3 minutes before transferring to cooling rack to cool completely.6. Transfer cookies back to baking sheet and place in freezer for 20 minutes. While cookies are chilling, remove ice cream from freezer and allow to soften so it is easier for scooping.

ASSEMBLE THE SANDWICHES:Place the chopped walnuts and mini chocolate chips in small bowls. Start spreading on the banana ice cream, a few tablespoons or so, onto the bottom flat side of the cookie, spreading evenly, before topping with another cookie. Sprinkle on crushed walnuts and mini chocolate chips, then place on a plate and transfer to freezer. Repeat this process with the remaining cookies.Store ice cream cookie sandwiches in freezer until ready to eat, 20 minutes at the most. Then DIG IN!