Combine all ingredients in a blender and blend until smooth. The consistency of the final product will depend on a number of things. For more liquid malt, use more soy milk. For a more "concrete" malt, use less and/or use a "harder" non dairy ice cream. Oatscream seems to get about as hard as a rock in the freezer so this would work well for a firmer malt.
As I mentioned above, you need Barley Malt powder for this recipe. It can be hard to find but is so worth it. As the name implies, this gives it the "malted" taste.
I have heard that you can find this at health food stores but I have never found it there. Barley malt powder should be a snap to find if you have a home brewing store in your area. If all else fails, you can order it online.