This is an adaptation of a gluten free recipe I found here and modified to suit what I had in the cupboard. I have to say it's even better than the original! I like the slightly salty edge that the salted cashews added, but if it doesn't appeal to you then use unsalted nuts. You could also use hazelnuts or other sweet nuts, but I would not recommend walnuts as they can add a bitterness. Coconut oil adds a special texture and lightness that can't be replicated using vegetable oil.
Note on coconut oil: 40g of oil might sound like a lot, but coconut oil is a 'good' oil rich in antioxidants and 'good' cholesterol. It solidifies at room temperature, so it's easy to weigh at that time. On warm days it will liquify at room temperature- in which case just use 2 tablespoons' worth.