How to Make It
Cut each zucchini lengthwise into 1/4-inch-thick slices. You should have 28 slices. Season with salt and pepper.
Lay the prosciutto over half the zucchini slices. Top with 2 small sage leaves and the Fontina. Cover with the remaining zucchini slices. Cover the zucchini with paper towels and press down to extract any excess moisture.
Beat the eggs in a shallow bowl. In a plate, season the flour with salt and pepper. Dip the zucchini in the egg, then dredge in the flour. Transfer to a plate.
In a large skillet, heat 2 tablespoons of olive oil until shimmering. Add the stuffed zucchini without crowding the pan and cook over moderately high heat until golden brown, about 2 minutes per side. Transfer to a baking sheet and keep warm in a low oven. Repeat with the remaining zucchini, adding more oil to the skillet as necessary.
Add some sage leaves to the skillet and fry until crisp. Cut the zucchini into triangles and transfer to a platter. Top with the fried sage leaves. Sprinkle with the Parmigiano-Reggiano and parsley and serve with the lemon wedges.