Step 1

Preheat the oven to 350 degrees F.

Step 2

Grease a 2-quart casserole dish or a 2-quart square baking dish.

Step 3

In a large pot of salted, boiling water, cook the noodles to al dente, according to the package directions.

Step 4

Drain the noodles and set aside.

Step 5

While the noodles are cooking, in a large skillet, cook the beef, while crumbling, until it is no longer pink, about 5-7 minutes. Drain the excess grease.

Step 6

Stir the tomato sauce, the basil, the sugar, the garlic powder, the salt, and the pepper into the beef and bring to a boil.

Step 7

Reduce the heat and simmer the beef mixture, uncovered, for 5 minutes.

Step 8

In a medium mixing bowl, use an electric hand mixer to beat the sour cream and the cream cheese together on medium speed until smooth.

Step 9

Stir the milk and the onion into the sour cream mixture.

Step 10

In the prepared casserole dish, layer 1/2 of the cooked noodles, 1/2 of the beef mixture, 1/2 of the cream cheese mixture, and the spinach.

Step 11

Top the spinach with the remaining beef mixture and then the remaining noodles.

Step 12

Cover and chill the remaining cream cheese mixture until needed.

Step 13

Cover the casserole dish with lightly greased foil and bake until it is heated through, about 45 minutes.

Step 14

Uncover the casserole dish and spread the remaining cream cheese mixture over the top of the casserole.

Step 15

Sprinkle the cream cheese mixture with the cheddar cheese.

Step 16

Bake the casserole, uncovered, until the cheese melts, about 10 minutes.

Step 17

Let the casserole stand for 10 minutes.

Step 18

Serve.