Suggestions Needed: Grilled Artichokes

Ever get those nasty thistles in your garden? You probably curse them, yank them out, and discard them. But did you know the artichoke is a species of thistle? The part you're familiar with is the artichoke's bud prior to blooming. Once it blooms, it's much to tough to eat.

I bought this artichoke at Weis Markets, my local supermarket. I've never grilled one before but thought I'd give it a try. After all, the past week has been full of cooking firsts.

From the recipes I read, they instructed me to either cut the artichoke in half or quarters. Here's what it looks like cut in half. It's rather pretty, isn't it?

I trimmed the outside leaves, which I read was an optional step but can be helpful since the leaves can be sharp. With my capacity to be able to hurt myself on the oddest things, I thought trimming would be a good idea.

Then I boiled the halves in a pot of water for about 8-10 minutes.

I brushed some oil, vinegar, and spices on the flat halves and stuck the on the grill - first upright, then face down.

Here's where I could use some help. I grilled the two halves for a few minutes, probably around 5-7 minutes. Some of the heart still seemed a little tough. So we stuck them back on for a few more. 

Maybe our heat wasn't high enough or maybe I should have cooked them longer. I'm not sure. After the second round of grilling, the artichokes looked a little more charred than shown here. The base of the leaves ended up soft, which was fine for eating.

Can anyone tell me how long you typically grill your artichokes? Do they grill better if I quarter them instead? I'd love to get some advice here!