Step 1

Heat a large skillet over medium-high heat. Cook and stir beef in the hot skillet until browned and crumbly, 5 to 7 minutes; drain and discard grease. Mix sugar, salt, garlic salt and tomato sauce into ground beef; simmer until flavors blend, about 20 minutes. Remove from heat, cover skillet, and cool to room temperature.

Step 2

Bring a large pot of lightly salted water to a boil. Cook egg noodles in the boiling water, stirring occasionally until cooked through but firm to the bite, about 5 minutes. Drain and cool slightly.

Step 3

Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch casserole dish.

Step 4

Mix sour cream, cream cheese, and onion in a bowl.

Step 5

Scoop half the noodles into the prepared casserole dish; top with half the sour cream mixture. Spoon half the ground beef mixture atop sour cream layer. Repeat layering with remaining ingredients. Top casserole with Cheddar cheese.

Step 6

Bake in the preheated oven until Cheddar cheese has browned, 25 to 30 minutes.