Heat the cream over a medium flame until just before boiling. Remove from the heat, add salt, pepper, nutmeg and set aside to cool slightly. In a bowl, beat the egg yolks with a whisk, then add the warm cream, grated Grana Padano and thyme. Mix well and pour the mixture into 4 ceramic cassolettes; bake in a preheated oven at 120°C for 30-35 minutes. When cooked, sprinkle with a tablespoon of grated Grana Padano and place the cassolettes under the broiler for a couple minutes. Serve immediately.