Score chestnuts by cutting a shallow cross on the flat side with the tip of a sharp knife and place in boiling water for 5 minutes till tender.
Peel as soon as they’re cool enough to handle. They’ll peel better when still warm. Make sure both skin and fine inner pellicle are removed.
Peel and deseed pumpkin and cut into roughly 2cm cubes. Place pumpkin, peeled chestnuts and sage in a baking dish. Toss with olive oil, salt and pepper. Place in a preheated 180C oven for 30 minutes. Remove from oven and let cool. Slice each chestnut into 5-6 slices.
Plate by stacking cubes of pumpkin in a pile on each plate, spoon ricotta around and scatter the sliced chestnuts on top.
Use the sage leaves as garnish and any pan juices over the top as dressing. Finish by sprinkling sesame seeds over.