Melt butter in a large skillet, add garlic and sauté mushrooms. Add herbs and mix. Reserve.
Peel ollucos and grate them coarsely. Reserve.
Prepare rice the usual way. When rice is cooking and water has just evaporated, place ollucos on top without mixing them with rice. Cover pan again and let rice cook completely.
Add mushrooms and combine with rice and ollucos. Add cream and parmesan cheese. Combine thoroughly and correct seasonings.