In a saucepan melt the butter over low heat, stir in the flour, and cook the roux stirring, for 3 minutes. Remove the pan from the heat and add the heated milk, in a stream, whisking. Simmer the mixture, whisking occasionally, for 5 minutes, add the nutmeg and salt and pepper to taste, and transfer the mixture to a large bowl. Whisk in the egg yolks, 1 at a time, whisking well after each addition, and whisk in the Parmesan. In a bowl with an electric mixer beat the egg whites with a pinch of salt until they are frothy, add the cream of tartar, and beat the whites until they just hold stiff peaks. Stir one-third of the whites into the mixture and fold in the remaining whites gently but thoroughly.
Spread the sponge batter evenly in a buttered 15 1/2 x 10 1/2- inch jelly-roll pan lined with buttered and floured waxed paper and bake it in a preheated 350-degree oven for 25 minutes, or until it is golden and firm to the touch. Cover the egg sponge with a sheet of buttered waxed paper, buttered side down, and a dish towel, invert a baking sheet over the towel, and invert the egg sponge onto the baking sheet. Remove the jelly-roll pan and the waxed paper carefully and trim 1/4-inch from the short sides of the egg sponge. Fill the egg sponge with the filling of your choice while it is still warm and flexible.
While the egg sponge is baking make the filling: In a skillet combine the corn and 1/2 cup of the cream and simmer the mixture, stirring occasionally, for 4 minutes. Add salt to taste and cayenne, stir in the scallions and the remaining 1/2 cup cream, and simmer the mixture, stirring occasionally, for 5 minutes, or until it is thickened and the cream is absorbed. Stir in the roasted pepper, the Parmesan, and salt and black pepper to taste.
Spread the filling over the warm egg sponge in an even layer, leaving a 1-inch border all around, roll the roulade jelly-roll fashion, beginning with a long side, and trim the ends on the diagonal. With the aid of the towel and the waxed paper transfer the roulade, seam side down, to an ovenproof platter, spread it gently with the butter, and sprinkle it with the Parmesan. Bake the roulade in a preheated 350-degree oven for 10 minutes, or until it is heated through and the Parmesan is melted. In a food processor or blender puree the roasted peppers, add salt to taste and the cayenne, and transfer the puree to a small bowl. Slice the roulade on the diagonal, serve it with the puree, and garnish it with the parsley sprigs. Yield: 4 servings as an entree or 8 servings as a first course