Place cooked and drained noodles in a buttered 1 quart casserole dish.
Mix sour cream, cottage cheese, minced onion, salt, powdered mustard and white ground pepper.
Mix the above with the noodles in the casserole dish; bake in a preheated 350 oven for 25 minutes. (The noodles on top should begin to brown.)
To be a bit more fancy, when the 25 minutes are over, pull the casserole out of the oven, smear it with a bit of butter, and allow it to cook another 5 to 10 minutes.
To be even more fancy, sprinkle some parmesan cheese on top of the butter before putting the casserole back into the oven.