Preheat oven to 350 degrees F.

Spray a 10 X 3-inch spring form pan with kitchen pan spray then wrap the outside of the pan in two layers of foil.  Also get an outer pan ready which is larger than the spring form pan to use as a water bath.

Place a tea kettle on to boil and hold hot while you prepare the tart.

*Wait to shred the potatoes until you are ready to saute. They will oxidize very quickly. I waited until the onions were cooking before starting to shred.

Shred the zucchini on the large holes of a box grater or if you have a shredder attachment for your food processor, use that.

Place into a dish towel or nut bag if you own one and squeeze out as much of the water as possible. Set aside.

In a very large skillet or saute pan, place two tablespoons of the oil and heat over medium high heat. Once hot, add the onions and cook three minutes.

As soon as you start the onions, peel and shred the potatoes then squeeze out as much water as possible using a dish cloth or a nut bag if you have one. They will start to oxidize but that is OK as they will be cooked immediately and the oxidization will not matter.

After the three minutes of cooking the onions, add two more tablespoons of oil and the butter as well as the potatoes and toss to coat. Cook for two minutes stirring often. They will still be undercooked but will cook further in the oven.

After the potato mixture has cooked two minutes, add the remaining two tablespoons of oil and then add the zucchini and garlic and toss and cook two minutes. This mixture will cook further in the oven and will not be completely cooked yet.

Remove from heat and spread out on a sheet tray to cool while you prepare the rest of the filling.

In a large bowl beat the eggs with the salt, pepper and nutmeg. Then add one cup of the grated Parmesan cheese and whisk.

Add the now cooled zucchini mixture and whisk to combine.

Pour into the prepared spring form pan.

In a small bowl, mix the remaining cup of Parmesan cheese with the bread crumbs and spread over the top of the tart. Spray the top with kitchen pan spray to help with browning.

Set the double foil lined spring form pan into the outer pan and pour hot water into the outer pan, about half way up without letting any water get inside the foil.

Place the pan in the water bath into the oven and bake until the center feels firm when touched, about 50-55 minutes.  Check water level after 30 minutes and add more as needed.

Ours took just under 55 minutes to bake.

Remove the spring form pan from the water bath and remove the foil.

Let sit five minutes then run a knife along the edge to loosen and then release the spring form outer ring.

Cut into eight wedges and serve.