Place the broth in a large saucepan along with the seasonings (1 1/2 teaspoons thyme, garlic chips, salt and pepper).
Trim off the dark green part of the leek. (Use for another purpose.) Take the white-light green portion and split in half lengthwise. Place that in a water bath and rinse well, changing water as needed in order to remove all dirt and sand from the leek. Once clean, slice the leek into thin half discs. Place into the pot of seasoned broth.
Peel potatoes and slice very thin by hand or by using a mandoline or food processor. Slices should be less than 1/4 inch thick. Place potatoes in the saucepan.
Preheat oven to 400 degrees.
Heat contents of the saucepan to a boil over medium-high heat. Reduce flame to a simmer and cook until the potatoes are tooth tender - you can bite'em but they still have some resistance - about 5 minutes.
Place the contents of the saucepan into 6 individual gratin dishes, ramekins or custard cups. Press down to level the tops. (should your mixture only partially fill the dishes, add a mixture of water and additional broth so that the tops of the contents is within a half inch of the lip of the dish.) Garnish with the remaining thyme.
Set the dishes on a baking sheet and bake for 30 minutes. Check for potatoes for doneness. Apply a *very* quick application of cooking spray to the tops to aide crispness. Cook an additional 10 minutes or until the potatoes are done and the tops are a crispy golden brown.
For Vegetarian do not use the Chicken Broth option.