Generously butter 2 (15 by 10 by 1-inch) baking (jelly roll) pans and line them with parchment paper. Preheat the oven to 350 degrees.
Over medium heat, melt the butter in a saucepan. Whisk in the flour, cayenne, and salt. Cook 3 to 5 minutes, stirring until the center bubbles. Remove from heat, and stir in the milk. Return to heat and cook 3 to 5 minutes more, stirring continuously, until the mixture thickens. Remove from heat.
In a large bowl, beat the egg yolks with a wire whisk. Gradually whisk in the flour mixture; beat until smooth.
Using an electric mixer, beat the egg whites and cream of tartar until stiff peaks form. Gently fold the whites into the yolks, being careful not to overmix.
Using rubber spatula, divide the batter between the 2 pans and spread evenly. Bake 15 to 20 minutes, until the roulade springs back when touched in the center. When completely cooled, invert the roulade sheets onto a clean surface, and discard the parchment paper.
Whip together the salmon, cream cheese, and dill, until light and fluffy. Spread the salmon mixture evenly on the surface of the roulade. Place 1 of the 15-inch roulade sides in front of you. Carefully roll it toward the other 15-inch side, until the width of the roulade forms a spiral of egg and filling. Cut each roulade into 10 slices. Refrigerate if not serving immediately.
Spread the roulade slices out on a greased baking tray in a single layer so that the sprial is on the top and bottom of each slice. Sprinkle with Parmesan cheese. Reheat in a preheated 350 degree oven for 8 to 10 minutes. Broil for 3 to 5 minutes, until lightly browned.