Preheat oven to 200°C (392°F) with grill and fan setting.
Place the camembert in an ovenproof dish. Make a diamond-shaped cut approximately 0.5 cm deep with a knife. Drizzle with the olive oil and place the rosemary sprigs on top.
Bake for 10 minutes until the cheese begins to melt. Cover with aluminum foil if needed.
Scatter the walnuts over the camembert and drizzle with honey. Serve warm.