This recipe came about because we love pears, fennel, hazelnuts, bacon and cream sauce. So I just kept messing around with ingredients until we had a winner. To justify the cream (hey, I didn't add butter too!) I read the health benefits of pears, fennel and hazlenuts out loud to the diners before eating and then we don't have ice cream for dessert.
This is a forgiving recipe because I need one when entertaining. Hey, who can go wrong with cream and bacon ! Feel free to add whatever vegetables you want into the shells if fennel isn't your thing. Sauteed arugula or spinach would be great. I use Pecorino Romano and Parmesan because in my view it doesn't overpower the pears, but use whatever you like.
My daughter's boyfriend the Italian Chef gave me the tip of adding enough pasta water to the pan the shells will be baked in to barely cover the bottom. This had made a difference - no more stuck shells.
Toss pears in olive oil and roast at 380F about 20 minutes.
Toss fennel in olive oil with salt and pepper and roast at 380 F at same time as pears are roasting. Roast fennel for 30 - 40 minutes.
Brown bacon. An easy way is to put it on cookie sheet covered with aluminum foil at 350F for about 30 - 45 minutes.
In a heavy large high sided pan place the cream, garlic, cayenne and rosemary. Bring to a boil over medium heat and cook for about 7 minutes, stirring regularly to prevent the cream from boiling over. Reduce the heat to medium low and cook for another 10 - 15 minutes longer until the mixture has thickened, remembering to stir regularly.
When the cream mixture has thickened add the cheese and mix until cheese has melted.
Add the bacon and the hazelnuts, stir in and set sauce aside.
Boil large pasta shells until al dente. Put in about a tablespoon of olive oil in the water which will help the shells from sticking together. When done, drain and keep about 1 cup of pasta water aside. Place shells in oven proof glass baking pan in which you have poured just enough pasta water to barely cover the bottom.
Fill pasta shells with fennel, then pears. When all the shells are filled pour sauce over the top. (If your sauce is too thick, thin it with a little pasta water before pouring it over filled shells.) Baked at 350F for 30 - 40 minutes.