- 1/3 cup California Olive Ranch extra-virgin olive oil plus extra for drizzling
- 1 large red onion, thinly sliced
- 2 large leeks (white bulb only), thinly sliced
- Salt to taste
- Coarsely ground black pepper to taste
- 1/4 cup white wine vinegar
- 1 large sweet potato, peeled and thinly sliced
- 2 large baking potatoes, peeled and thinly sliced
- 1 large zucchini, stem end trimmed, and thinly sliced
- 1 summer squash, ends trimmed, and thinly sliced
- 1/3 cup fresh thyme leaves
- 1-1/2 cups grated Parmigiano-Reggiano cheese
Pour the California Olive Ranch extra-virgin olive oil into a large skillet or Le Creuset-type casserole dish that is at least 12x2½ inches.
Over medium-low heat, cook the onion and leeks until they are soft; season them with salt and pepper as they cook. Cooking them slowly will allow the onions to release their sugar and give
a great flavor to the dish. When they are soft, raise the heat to high and pour in the white wine vinegar; cook, stirring occasionally, until the
vinegar is nearly evaporated.
Turn off the heat. Spread out the onion mixture evenly in the casserole. Preheat the oven to 350°F.
Begin making single layers of each vegetable over the onion mixture starting with the sweet potato; sprinkle the layer with salt and pepper,
about 1 teaspoon of the thyme, and 2 tablespoons of the cheese. Drizzle a little olive oil evenly over the potato.
Make a second layer like the first, using the baking potato slices. Make a third layer with the zucchini, and a fourth layer with the summer squash.
Repeat the layering so there are eight layers in all. Sprinkle the remaining cheese evenly over the top of the vegetables and drizzle them with olive oil.
Bake covered for 45 minutes; uncover and bake 5 minutes longer.
Serve the casserole by cutting it into wedges or scooping it from the dish.
Chef's Note: Vegetables are the foundation of Italian cooking. Just a glance at the Italian food pyramid tells us that vegetables constitute a great part
of the Italian diet. This unique vegetable casserole for a crowd is layered with paper-thin slices of zucchini, summer squash, potatoes, and sweet
potatoes. It is fun to put together, and a vegetarian’s dream. To slice the vegetables, use a mandolin (a French slicing tool), or the slicing hole
on a four-sided cheese grater, or the slicing attachment for a food processor. This casserole is perfect as part of a buffet.
TIP: To prepare the vegetables ahead of time, slice them all (except the baking potatoes) and keep them tightly wrapped separately in
plastic wrap. Refrigerate until ready to assemble. Slice the baking potatoes, put them in a bowl, cover with cold water, and refrigerate.
When ready to use, drain off the water and pat the potatoes dry.
Recipe credit: Ciao Italia Slow and Easy
( St. Martin's Press, 2007), by
Mary Ann Esposito. Reprinted with permission from St. Martin's Press