Choose an ice cream of any flavor you like, and put 2-3 scoops into bowls or cups. Crush 3-4 biscuits on top of it and sprinkle it with chopped or ground walnuts.
Add a topping to suit the ice cream flavor. You can use a jam or jelly, diluted with 1-2 tablespoons of water to make it slightly runny.
You can also grate some chocolate on top of it, if the biscuits and ice cream are cocoa-flavored.