Lengthwise cut buns into 2 halfs. Preheat the oven to 170-180 degrees Celsius. Grease buns with low-fat cream, season with salt and pepper, sprinkle with chopped chive and diced ham. Cut onion into circles, sprinkle the buns. Sprinkle with grated cheese on the top. Bake in the oven for 10-15 minutes until the buns are lightly browned. Serve immediately!