First preheat oven to 400 degrees,then begin food prep.In a large sauce pan bring water to boil for macaroni (fill sauce pan about 1/2 full of water then you may want to add salt so macaroni won't stick.)After the water comes to boiling point add macaroni. Cut fresh onion,measure about 1/4 cup then set aside for mixture.Brown the hamburger in a skillet adding onion powder,garlic powder,and salt & pepper to taste. Mix together in a separate bowl;cream of cheddar,sour cream, parmesan cheese,and diced onion.When hamburger has finished browning set aside.Drain macaroni when finished and mix in,cubed velveeta cheese,when the cubed cheese seems to be almost melted add in the mixture from the separate bowl.Slowly mix in milk then add hamburger slowly.Lightly grease 11"x 13" deep cake pan then pour in macaroni/hamburger mixture and spread evenly.Add a top layer of Kraft cheese then top with crumbled Ritz crackers.Cover with aluminum foil and bake,remove foil after about 20 mins.then bake another 10 mins. or until golden brown.