How to Make It
Preheat the oven to 375°. Spread the hazelnuts in a pie plate and toast for 8 minutes, or until fragrant. Let the nuts cool, then coarsely chop them.
In a small saucepan, boil the chicken stock until reduced to 3/4 cup, about 15 minutes; keep warm.
Bring a large pot of salted water to a boil. Add the Brussels sprouts, cover and cook until crisp-tender, about 5 minutes. Using a slotted spoon, remove the Brussels sprouts and pat them dry. Return the water to a boil. Add the orecchiette and cook until al dente, 12 to 15 minutes; drain.
Meanwhile, in a large, deep skillet, cook the bacon over moderately high heat until crisp, about 6 minutes. Drain the bacon on paper towels. Add the butter to the skillet and cook over moderately high heat until browned and nutty, about 3 minutes. Add the Brussels sprouts and hazelnuts and cook until heated through, about 2 minutes. Add the orecchiette along with the reduced chicken stock and simmer, stirring, until the sauce is slightly absorbed, about 2 minutes. Stir in 1/2 cup of the Parmigiano cheese, season with salt and pepper and transfer to a large serving bowl. Garnish with the bacon and the remaining 1/2 cup of cheese and serve.