Heat large pot of water to boiling for pasta.When water comes to a boil, add salt.
Meanwhile, heat cream and mascarpone in medium saucepan over medium-low heat about 2 minutes; do not allow to boil.Stir in Gorgonzola and cook, stirring occasionally, until melted, about 5 minutes.
Toast hazelnuts at 350 degrees (you can use toaster oven) until golden, 8-10 minutes.Cool slightly, then finely chop, discarding any skins that fall off.Transfer to large serving bowl and add Parmesan.
Cook fettuccine in boiling water until tender but still firm to the bite; drain.
Add pasta to hazelnuts.Pour cheese sauce over pasta, add parsley and pepper, and toss to combine.Serve immediately with additional pepper, if desired.
