Step 1

Pierce potatoes several times with fork. Microwave until tender, turning once, about 16 minutes total. Cut potatoes in half lengthwise; scoop potato flesh into bowl; discard potato skins. Mash potatoes until smooth. Mix in egg. Sift flour, salt, pepper, and nutmeg over potato mixture; stir to combine. Knead gently. Divide dough into 8 pieces. Roll each piece on work surface into 1/2-inch-diameter rope. Cut dough into 1-inch lengths and make grooves in each piece with fork.

Step 2

Cook gnocchi in large pot of boiling salted water until gnocchi are tender and rise to surface, about 5 minutes. Using slotted spoon, transfer cooked gnocchi to warm platter. Bring cream to simmer in heavy medium saucepan over medium heat. Add Gorgonzola, whisking until melted. Spoon sauce over gnocchi. Sprinkle with chives and Parmesan, if desired; serve.