1.
Preheat oven to 375 degrees F. Line a 15x10x1-inch
baking pan with foil, extending foil about 1 inch over edges of pan.
Grease and lightly flour foil; set pan aside.

2.
In a medium saucepan, melt butter. Stir in flour and
pepper. Gradually stir in milk. Cook and stir until mixture is
thickened and bubbly. Cool slightly. Place egg yolks in a medium bowl;
gradually stir in milk mixture.

3.
In a large bowl, combine egg whites and cream of
tartar. Beat with an electric mixer until stiff peaks form (tips stand
straight). Fold some of the beaten egg whites into the egg yolk mixture.
Fold egg yolk mixture into the remaining beaten egg whites. Spread in
the prepared baking pan.

4.
Bake about 20 minutes or until souffle is puffed and a knife inserted in center comes out clean.

5.
Meanwhile, place a long sheet of heavy foil (about
22×18 inches) on a large baking sheet. Generously grease the foil.
Immediately loosen edges of souffle from baking pan. Invert souffle onto
the foil-lined baking sheet. Carefully peel off foil.

6.
Place ham and cheese slices in single layers on top
of souffle. Starting from a short side, use foil on baking sheet to lift
and help roll up souffle. (Don't roll the foil inside.) Use foil to
lift souffle roll into a 13x9x2-inch baking pan. Fold the foil over
souffle roll to cover; chill for 2 to 24 hours. Prepare Parsley Sauce;
cover and chill for up to 24 hours.

7.
Preheat oven to 350 degrees F. Bake souffle roll,
covered with the foil, about 45 minutes or until heated through.
Meanwhile, shake sauce; transfer to a medium saucepan. Cook and stir
over medium heat until thickened and bubbly. Cook and stir for 2 minutes
more.

8.
To serve, uncover souffle roll. Use the foil to lift
souffle roll from pan. Using two large spatulas, transfer souffle roll
to a warm serving platter (or use foil to roll souffle onto platter). If
desired, spoon a little sauce over souffle roll. Slice with a serrated
knife and serve with the remaining sauce. If desired, garnish with
snipped parsley.