Cook sausage and onion in a large skillet over medium heat, stirring until sausage crumbles and is no longer pink; drain well. Return sausage to skillet; add 1 cup Cheddar cheese, cream cheese, and marjoram, stirring until cheeses melt.
Spoon 3 tablespoons filling down center of each Crêpe.
Roll up, and place, seam side down, in a lightly greased 13- x 9-inch baking dish.
Bake, covered, at 350° for 15 minutes. Stir together sour cream and butter; spoon over crêpes. Bake 5 more minutes. Sprinkle with remaining 1 cup Cheddar cheese and parsley. Serve with sliced tomato.
Note: Crêpes may be assembled and frozen. To reheat, let stand for 30 minutes at room temperature. Bake, covered, at 350º for 40 minutes. Proceed as directed.
My mother started fixing these when the recipe was first published, in the 90s. I have fixed them for Christmas just as she did. A couple of times I tried a new recipe for breakfast and was always asked to go back to these. The beauty of these is that you can do all of it ahead of time, cover well and freeze. It's wonderful! Not too mention if I can make crepes everyone else can. They're easy once you get the hang of it and the whole recipe is very tasty and catches everyone off guard.