Preheat oven to 180 °C or 350°F fan forced and either grease/line a standard loaf tin, or use a silicone one.
Add 165 g or 5.8 oz of the raw almonds to dry mixer bowl, mill for 10 sec/speed 9/MC on or until fine. Set aside.
Add remaining raw almonds and mill for 10 sec/speed 9/MC on.
Add the rest of the ingredients, including the reserved ground almonds, but excluding the walnuts and dates, and mix for 15 sec/speed 5/MC on.
Scrape bowl down, add walnuts and dates, and blend for a further 5 sec/speed 4/MC on.
Remove cake batter to prepared loaf tin, garnish with banana slices if using, and bake in the oven for 40 min or until cooked. Please note, depending on your oven and the size/depth of your loaf tin, timing can be variable. You want a skewer to come out clean.
Allow cake to cool completely before slicing.