Adventures in making Burnt Sugar Essence

This year I wanted to try the West Indian Black Cake recipe as it appears in Laurie Colwin's "Home Cooking" (a few years ago I made Nigella's version, which skirts the Burnt Sugar Essence issue by substituting molasses. But I was still intrigued by the challenge of making/finding this odd ingredient.)
Colwin's instructions are, at best, vague: If it's unavailable, Betty suggests putting a pound of sugar in a heavy skillet with a little water and boiling it gently until it begins to turn black. You do not want to overboil. It should be slightly bitter, black and definitely burnt.
Probably makes perfect sense to an old fashioned pro, but some of us need more help than that. Anyway, I did just as I understood it, adding water at the start and letting it gently boil. For a long time. Eventually the water started to evaporate out, so I added some more. After 45 minutes I figured nothing was going to turn black, and settled for the molasses-brown color I had achieved. Off the heat, the sugar near the bottom of the pan hardened and crystallized, while the top remained liquidy enough to pour out. I thought, it's now or never with these cakes, or the sugar will harden up.
As you can see, these cakes are nowhere near black, and Colwin maintains that her babysitter's cake was indeed black. They are not even close to chocolate brown, but they taste delicious nevertheless.
Some searching around on the internet let me to some adventurous bakers who have gone this path before me. They say, melt the sugar to a syrup, then remove from heat, add water and stand back. When it stops reacting violently, you have burnt sugar essence.
I still have half a bowl of fruit marinating in the fridge. Guess I'll try their suggestion next time, maybe for Easter.