Here is a delicious supper or luncheon dish that can be prepared ahead and gratinéed just before serving. You'll need to cook the omelettes according to one of the master recipes (either the scrambled omelette or the rolled omelette), but leave them slightly underdone.
Slip each omelette as it is made onto a buttered plate, then slide it onto a buttered platter, arranging the omelettes side by side. Cut a slit along the length of each omelette to within ½-inch of the 2 ends. Fill the slits with the tomato purée. Just before serving, pour the cream over the omelettes, and sprinkle with cheese and melted butter. Set the buttered platter 3-inches from a hot broiler for 1-2 minutes to reheat the omelettes and to brown the cheese lightly, but do not let the omelettes overcook. Serve immediately.