Cut 1 1/2 lemons in half and squeeze the juice into a large bowl of water.
Add the squeezed lemons to the water also.
Slice 1 lemon and set aside with remaining 1/2 of a lemon.
Trim the artichoke stems and pull away any tough leaves and discard.
With a scissors, trim away the tops of the thicker leaves of the artichokes, just a little, so that they do not prick you when eating them.
To avoid the artichokes turning brown after cutting, steps 7 and 8 should be carried out quickly one artichoke at a time.
With a chef knife, trim approximately 1 inch off the top of each artichoke and discard, then cut it in half lengthways.
With a spoon, scoop out the fuzzy choke, from each half, then immediately drop it into the lemon water to avoid browning.
Remove an artichoke half out of the lemon water, pat with a paper towel, then place in baking tin.
Fill the center of the artichoke half with garlic and top with a half a sprig of thyme, and then a slice of lemon.
Repeat steps 9 and 10 until you have all of the artichoke halves in the baking tin.
Carefully turn each artichoke half over, using the lemon slice to stop the garlic and thyme from falling out.
Any thyme you have left over should be scattered in the base of the baking tin.
Drizzle the artichokes with olive oil, twice.
Loosely cover baking tin with aluminum foil and place in a preheated oven at 400.
Cook until artichokes become tender (approx. 50 mins to 1 hour)
Once artichokes are tender, remove baking tin from oven and remove roasted garlic and place in a bowl.
Turn each artichoke half over so that the cut side is facing upwards, leave the lemon and the thyme in the bottom of the baking tin.
Raise temperature in oven to 425.
Squeeze remaining half of lemon over the artichokes and sprinkle with a little salt to taste and return artichokes to oven without the foil.
Allow artichokes to brown just a little, then remove from the oven.