Raw slab sugar is also known as brown sugar in pieces. They are sugar blocks made from brown sugar. If unavailable, you can substitute in dark brown soft sugar to taste. Both raw slab sugar and black vinegar can be purchased at Chinese/Oriental speciality stores.
Made this for dinner tonight after realizing I had all of the ingredients on hand, and really liked the result. I was concerned about the garlic and shallots because they were nearly blackened by the time I added the onions to brown them. I added the sauce with some warm water and, let it reduce a for about a minute. The meat was tender, and the taste was awesome. I will make again, thank you! - 22 Sep 2014
Easy to make, I swapped the slab sugar for brown, and black vinegar for malt. It tasted fab. I've tried a few of ton's recipes now and not been disappointed once. - 19 Sep 2013