-Preheat the oven to 350 degrees Fahrenheit (175 degrees Celsius)
-In a large bowl with a hand mixer or the bowl of a stand mixer with the paddle attachment, cream together the butter, sugars, vanilla, and bananas. Add the egg and mix well.
-In a dry skillet, toast the walnuts, stirring occasionally over medium heat until you begin to smell them. Remove from the heat and allow them to cool.
-Whisk together the flour, cinnamon, salt, baking soda, and oats in a large bowl. Add the flour mixture to the wet mixture, beating on low until thoroughly blended. Add the white chocolate chips and toasted walnuts to the batter and mix well, scraping down the sides occasionally.
-Drop the batter in tablespoon-size portions onto parchment-lined baking sheets, 12 per sheet. Bake two sheets in a preheated oven for 7-10 minutes, rotate the sheets, and continue baking for an additional 7-10 minutes. Remove baked cookies to a cooling rack and continue the same steps with the remaining batter.
Notes
Store cookies in an airtight container at room temperature for up to 7 days.Cookies may be frozen after baking. Store them in an airtight freezer container for up to 3 months.Cookie dough may be frozen before baking for up to 2 months. Wrap the dough well in plastic wrap and thaw completely in the refrigerator. Once thawed, continue on with the recipe as written.