Preheat oven (electric cooker: 250 °C/circulating air: 225 °C/gas: see manufacturer). Clean broccoli, cut into florets and wash. Peel the broccoli stems, cut them in half lengthwise and cut them into pieces about 1 cm wide.
Cook the florets and stems in 1⁄4 l boiling salt water for about 4 minutes.
Dice gorgonzola. 1⁄3 Lift out broccoli with a skimmer. Finely puree the rest with the cooking water, cream and gorgonzola using a hand blender. Season broccoli-cheese sauce with salt, pepper and nutmeg.
Mix the sauce with the uncooked tortelloni and the remaining broccoli. Pour into a flat greased casserole dish and grate the Parmesan cheese over it. Bake in a hot oven for 8-10 minutes until golden brown.