Pre-heat oven to 400F/200C. Grease and flour or spray an 8 inch springform cake pan or line a regular 8 inch with parchment paper.
In a large pot of salted water boil the unpeeled potatoes until tender, approximately 15-20 minutes. Drain, then peel and mash, place in a large bowl. Add the softened butter, yolks, cornstarch, ¼ salt, pepper and 1 teaspoon parsley.
While the potatoes are cooking, in a medium frying pan add the oil, chopped shallot, sliced zucchini, ¼ teaspoon of salt, dash or two of pepper and 1 teaspoon of chopped parsley, cook until the zucchini is lightly golden.
Transfer ½ the potato mixture to the prepared pan and gently flatten and form a small border on the sides. Top with the cooked zucchini then the cubed cheese. Place pieces of the remaining potato mixture on top (large coarse crumbs). Top with the bread crumbs and dot with 1-2 tablespoons of butter. Bake for 30-40 minutes or until golden brown on top, broil for 2-3 minutes to brown if necessary. Let sit 5 minutes, sprinkle with a little finely chopped parsley before serving. Enjoy!
Notes
To boil the potatoes, place the unpeeled potatoes in a large pot, cover with water and heat until boiling, cook until fork tender. Cooking the potatoes unpeeled keeps them from absorbing too much water. Peel while still hot, hold the potato with a fork and peel gently with a knife.The pie can be made the day before, be sure to wrap well in plastic wrap and refrigerate. The day after continue with the baking instructions.Store any leftovers in an airtight container in the fridge. It will keep for up to two to three days refrigerated. It can also be frozen, cool the pie completely then freeze in a freezer container it will keep for up to a month in the freezer. Thaw in the fridge then reheat in the oven or microwave.