Place venison in a bowl. Add the flour, and toss to coat the cubed meat. Once coated, add venison to the skillet, and brown according to the following directions below.
In a 10-inch skillet, over medium heat, add the vegetable oil. Cook and stir the venison until it's cooked about 3/4's of the way done; stirring often so the meat doesn't stick to the skillet. Now add the diced onion, and continue cooking the meat until it's browned evenly. Once the venison is browned, cover the skillet, and remove skillet from the heat.
Preheat the oven to 325 degrees.
In a 2-1/2 quart casserole baking dish, add the tomato sauce, garlic powder, salt, pepper, and the Worcestershire sauce; stir to mix.
Add the cooked venison to the casserole dish; stir to coat the meat in the tomato sauce. Cover the casserole dish; place dish in the oven, and cook for 1 hour and 30 minutes, but be sure to stir the meat mixture after the first 30 minutes of cooking time.
After 60 minutes of cooking time, remove casserole from the oven, add the sliced mushrooms and the sour cream, and stir. Cover, and place the casserole back in the oven to cook for another 30 minutes.
About 15 minutes before the meat mixture is done cooking, cook the egg noodles according to package directions. (I cooked mine with a bit of vegetable oil, and with out any salt, for exactly 9 minutes.) Once I drained off the water, I stirred in a bit of butter, so the noodles wouldn't stick together.
Once the noodles are cooked, and the meat is cooked, add desired amount of noodles to each dinner plate, and top with the stroganoff. Sprinkle each plate with a bit of the dried parsley, and serve. Refrigerate any leftovers.