-
1
Put an oven rack in the center of the oven.
-
2
Preheat the oven to 400 degrees F. Line a baking sheet with parchment paper.
-
3
Using the tines of a fork, prick the skins of the potatoes all over and arrange on the prepared baking sheet.
-
4
Bake for 1 to 1 1/4 hours until tender and cooked through.
-
5
Remove from the oven and let cool until warm enough to handle, about 20 minutes.
-
6
While the potatoes are cooling, in a medium skillet, heat 3 tablespoons of olive oil over medium-high heat.
-
7
Add the onion and cook, stirring frequently, until soft, about 5 minutes.
-
8
Add the mushrooms, garlic, 1/4 teaspoon salt and 1/4 teaspoon pepper.
-
9
Cook until the mushrooms are golden and most of the liquid has evaporated, about 6 minutes.
-
10
Put the mixture into a medium bowl.
-
11
Cut the potatoes in half lengthwise and, using a small spoon, scoop out all but 1/4-inch of the flesh.
-
12
Add the potato flesh to the mushroom mixture.
-
13
Add the butter, oregano, and 1 cup of the cheese.
-
14
Mix well.
-
15
Season with salt and pepper, to taste.
-
16
Arrange the potato halves, cut side up on the baking sheet.
-
17
Using a pastry brush, brush both sides of the potatoes with the remaining 3 tablespoons of olive oil and season the inside with salt and pepper, to taste.
-
18
Spoon the mushroom mixture into each potato half.
-
19
Arrange 1 half-piece of prosciutto on top and sprinkle with the remaining cheese.
-
20
Bake until the cheese is melted and the prosciutto is crispy, about 20 to 25 minutes.
-
21
Remove from the oven, transfer to a serving platter, garnish with chopped parsley and serve.
