Start by soaking the cashews in water for at least 4 hours or overnight to soften them and make them easier to blend. You can also do this with the dates.
In a blender, combine the full-fat coconut milk, ripe bananas, soaked cashews, pitted dates (or sweetener substitute), and vanilla extract.
Blend the ingredients until smooth and creamy. Once the mixture is smooth, pour it into ice cube trays and freeze until solid, typically for at least 6 hours or overnight.
When ready to make the ice cream, let the frozen cubes thaw for a couple of minutes to soften slightly.
Transfer the thawed cubes into a food processor and pulse until you achieve a crumbly texture.
Add dark chocolate and walnuts to the food processor and blend until the mixture is smooth and scoopable, with small chunks of chocolate and walnuts throughout.