then top with your bread crumb mixture. Bake and the top will turn a beautiful golden brown. It almost seems like it could be healthy, but it's not!
I just can’t wait to bake this little side dish for my Thanksgiving dinner. I made this ahead of time and popped it into the freezer. I will take it out of the freezer two days before I am ready for it. You could also make this a few days before as well and just pop it into the refrigerator until you are ready to bake.
The flavors are so amazing with the onions, béchamel sauce, gruyere cheese and crunchy topping. Your guests will flip over this yummy side.
- 6 tablespoons butter
- 1 tablespoon olive oil
- 3 large sweet onions, cut in half then thinly sliced
- 2 pounds zucchini, sliced ¼ inch thick (about 4 zukes) use a mandolin to get even cuts
- Kosher Salt
- White pepper
- ¼ teaspoon ground nutmeg
- 2 tablespoons all-purpose flour
- 1 cup milk
- ¾ cups Panko bread crumbs
- ¾ cup grated Gruyere cheese
- ¼ cup shredded Parmesan cheese
- Preheat oven to 350 degrees.
- Spray an 8x8 square baking dish, set aside.
- For the onions and zucchini: In a large sauté pan melt two tablespoons of butter and one tablespoon of olive oil. Once hot, place the sliced onions over medium high heat for first 5 minutes, then reducing the heat to medium to low for about 20 minutes or until tender and deep caramel color. Season with salt and pepper in the beginning. Set aside.
- While the onions are cooking, in a separate large sauté pan add two tablespoons of butter. Melt. Add the zucchini. Season with salt and pepper, sauté until tender, gently turning. About 10 minutes. Remove from heat.
- For Bechemel sauce: In a separate sauté pan add the remaining two tablespoons of butter, melt. Whisk in two tablespoons of flour. Let the "rawness" of the flour cook out, about two to three minutes. Whisk in the milk until smooth. Season with salt, pepper and nutmeg. Set aside.
- Assemble the gratin. I like to line the bottom of the pan in neat little rows, over lapping the zucchini, until bottom of pan is covered. Top with ⅓ of the béchamel sauce. Top with half the caramelized onions, half the Gruyere cheese. Repeat.
- After second layer of zucchini, onions, cheese and béchamel, top with remaining zucchini and remaining béchamel sauce.
- In a small bowl melt 3 tablespoons butter, toss with the Panko bread crumbs and ¼ cup of Parmesan cheese.
- Spread the bread crumbs evenly over top.
- Bake for about 20 minutes, or until bubbly and browned.