When you grate a block of soap and reform it through the hot process, it's called Milling. If you mill the same batch of soap 2 more times or once more under steel rollers, it's called French Milling. The end result is a 17th century luxury good; denser, creamier and more fragrant bar of soap.
I like to use this method on homemade soaps even though it is more tedious. Mainly because this process breaks down the caustic lye making the soap gentler and safer for home use.
This batch here is Lemon Mint. When I run out of essential oils, I put in medicated oil or wintergreen. It's all for external application anyway.