Preheat oven to 350°F and butter or spray 9 x 13 casserole dish with cooking spray. Grate cheddar and Monterey Jack cheeses and add to a separate bowl. Toss to combine.
Heat a large skillet over medium-high heat. Add the ground beef and sausage together, breaking up with a wooden spoon, and cooking until the crumbles are nearly browned. Remove from skillet and spoon onto paper toweling to drain fat.
Return the skillet to the heat and add the onions. Cook until the onions have softened about 6 to 8 minutes. Add the fresh garlic and cook for 1 minute more, stirring constantly to prevent burning. Remove skillet from heat.
Add the beef and sausage mixture back to the skillet and stir to mix with the onion. To this add tomato sauce, stirring to combine. Place back over heat and and simmer on low. If you desire heat, add a pinch of red pepper flakes now. Pro Tip: If the meat mixture appears too thick when you get ready to assemble, use a ladle and stir in some of the starchy pasta water before draining the pasta. Use JUST ENOUGH to thin it out slightly.
Bring a large pot of water to a boil. Add a teaspoon salt and a teaspoon of any oil to help the cooked noodles avoid sticking. Add the egg noodles and cook according to package directions minus 1 minute. Noodles should be slightly under cooked. Drain and set aside.
In the barrel of a food processor, whip the cottage cheese for 1 to 2 minutes until very smooth. This step is optional. You may add the cottage cheese straight from the container. Cottage cheese oftentimes poses a textural issue for picky eaters, so I whip it first.
In a medium bowl, whisk together the (whipped) cottage cheese, sour cream, chopped green onions (green and light green parts only), Italian seasoning, garlic powder, onion powder, and black pepper until smooth and well combined. Add the sour cream mixture to the cooked pasta and stir to coat the noodles well.
To assemble the casserole, add half of the noodles to the prepared baking dish. Top the pasta with half of the pasta sauce, and then sprinkle with half of the cheese. Repeat the layers using remaining noodles, remaining sauce, and a final layer of cheese. Sprinkle modestly with additional black pepper only if desired.
Bake for 25 to 30 minutes, or until all cheese is melted and bubbly. Carefully remove the baking dish from the oven and serve immediately with a side salad and a slice of garlic bread. Pass parmesan cheese tableside for those needing an additional boost of cheesy goodness ;-)