Place the dried porcini in a bowl and cover them with the boiling water. Let them soften in the water for about a half hour.
Being careful to save the liquid, drain them through a strainer or sieve lined with cheesecloth, then squeeze them. Rinse thoroughly, then squeeze them dry and chop them coarsely.
Preheat your oven to 400 degrees and rub the inside of a three quart gratin dish with the cut side of the garlic clove.
Combine the fresh chopped chanterelles with salt in a large, heavy skillet and cook over medium heat until they begin to release their moisture. This should take only one or two minutes, depending on the size and weight of the skillet.
Continue to cook the mushrooms while stirring them for about five minutes, or until most of the moisture has evaporated.
Add three teaspoons of the olive oil, the chopped porcini, the minced garlic, and the thyme. Continue to cook for a few minutes, until you can smell the garlic.
Add the red wine and pepper, and cook, stirring, for a short time, or until the wine has been absorbed.
Remove from heat and mix with the potatoes.
Arrange the mixture in the gratin dish. Measure out three cups of the liquid reserved from soaking the porcinis and pour it over the mushroom and potato mixture.
Bake for about 90 minutes, or until the potatoes are tender and the top is crusty. Several times during baking, stir the potatoes from the bottom up to the top.
When the top begins to turn golden brown, sprinkle with the cheese and the remaining olive oil.
Continue baking until the top is a rich, golden brown and the cheese is bubbling.
Serves four to six.