2 to 3 pounds zucchini, a.k.a. 1 ginormous zucchini or several medium-sized ones
1/2 cup walnuts
1 pound sausage
1 onion, diced
8 oz mushrooms, diced
3-4 cloves garlic, minced
2 tablespoons minced sage
2 eggs
1 cup shredded pecorino cheese, divided

2 to 3 pounds zucchini, a.k.a. 1 ginormous zucchini or several medium-sized ones 1/2 cup walnuts 1 pound sausage 1 onion, diced 8 oz mushrooms, diced 3 -4 cloves garlic, minced 2 tablespoons minced sage 2 eggs 1 cup shredded pecorino cheese, divided

Pre-heat the oven to 375° F. Find a rimmed baking dish large enough to fit your zucchini halves. I ended up using a turkey roasting pan.
Cut the zucchini in half lengthwise and scoop out the seeds. Leave an inch or so of zucchini. Set the zucchini in the baking pan cut-side up and seasoning it with olive oil, salt, and pepper. Pour a quarter inch of boiling water into the pan, cover with foil, and bake for 10 minutes, just until the zucchini is no longer raw. Set aside to cool enough to handle.
Spread the walnuts on a baking sheet and roast them alongside the zucchini for 5-10 minutes, until fragrant. Chop into small pieces and set aside.
Leave the oven on and set at 375°F.
Heat a large skillet over medium-high heat. Brown the sausage, breaking it up into medium-sized bits as you go. Transfer to a bowl and drain off all but a teaspoon of the grease. Add the onions to the pan with a good pinch of salt, and cook until soft and golden. Add the mushrooms and another pinch of salt. Cook together until the mushrooms have turned golden and any moisture they released has evaporated. Stir in the garlic and sage. Cook for about thirty seconds until fragrant.
Combine the walnuts, cooked sausage, onions, and mushrooms in a large bowl. Taste and add more salt or other seasonings to taste. Beat the eggs together. Stir the eggs and 3/4 cup of the pecorino into the stuffing mixture.
Pat the zucchini dry and fill the cavity with the stuffing. Go ahead and really pack the filling in there before mounding it on top. This will help it hold together when you slice the zucchini later.
Drain the liquid from the baking pan, rub it with a little butter or olive oil, and place the stuffed zucchini back inside. Cover with foil and bake for 30 minutes. Uncover, sprinkle the remaining cheese over the zucchini, and bake for another 10-15 minutes until the filling is bubbling and the cheese is crispy.
Allow the zucchini to cool slightly. Slice into portions and serve. Leftovers will keep refrigerated for one week.