Potatoes au Gratin

Preheat the oven to 350 degrees.

Heat the butter in a large sauté pan and cook the onions over a medium heat. Reduce the heat, cover and continue cooking until the onions are caramelized, about 15 minutes.

In a large pot, combine potatoes, stock and cream (or yogurt) and season with salt and pepper. Simmer, stirring gently so as not to break the potato slices. Cook until barely tender, about 10 minutes. Use a slotted spoon to transfer a layer of potatoes into a buttered, deep 9 x 13 baking dish. Add enough potato liquid from the pot to cover (and reserve any leftover). Sprinkle with the Parmesan cheese and add a layer of onions. Repeat until the dish is full. Leave at least 1-inch of rim showing.

Combine breadcrumbs and asiago cheese and sprinkle over the top. Cover the baking dish and bake for 30 minutes. Check the potatoes - they should be getting soft. Take the cover off and check the liquid. If it seems in danger of burning, add any leftover liquid, but you don't want it to be wet when done, just moist. Also, you want the potatoes to hold together - not to be mushy. Cook uncovered for 10 - 15 minutes more. When the potatoes are done, turn the broiler on and put the baking dish under the broiler for 2 minutes so that the breadcrumbs turn golden brown.