The foam turns out to be pretty easy – I used the technique that I talked about from our second night of class of coming up with a simple vegetable “juice” – in this case, I peeled a section of horseradish root and ran it through the blender with a cup or so of water, blended it for about 5 minutes, then let it sit another 10-15, and then strained it. Just before ready to serve, I added a spoonful of soy lecithin granules to it, which gives the bubbles some tensoactive strength, so that the foam doesn’t just immediately collapse again – and then used a hand blender to foam the liquid (half in, half out of the liquid to make sure a good amount of air gets incorporated).