Preheat oven to 400℉. Heat the olive oil in a medium saucepan over medium heat. Add the onion and saute until soft and translucent, about 3-4 minutes.
Add the garlic and cook stirring constantly for about 20 seconds, just until fragrant.
Add the ground beef and cook until no longer pink, this takes about 3-4 minutes.
Stir in the sour cream, tomatoes, and tomato sauce, bring the mixture to a low boil. Stir to mix, about 1-2 minutes.
In a medium bowl, mix together the Parmesan, Ricotta, basil and egg.
Spread 1/3 of the ricotta cheese mixture on the bottom of a small casserole dish.
Place one noodle over the cheese mixture.
Layer with noodle, cheese mixture, and sauce, and mozzarella.
Repeat until you've used all your ingredients.
Cover the baking dish tightly with aluminum foil. Bake for 20-25 minutes, until bubbly. Remove foil and bake an additional 5-7 minutes until cheese is browned. Let cool for 10-15 minutes before serving.
Notes
You can simplify even further by using your favorite marinara sauce and adding g=cooked ground beef. Bertolli makes a small 8-ounce jar of marinara which is perfect for one-person.
No sour cream, then substitute heavy cream or plain Greek yogurt.
If you don't want to use egg, my favorite substitute is sour cream, you can also increase the amount of ricotta cheese.
Ground turkey can be substituted for the ground beef.
Reheat leftover lasagna in the oven or microwave. To keep it moist and flavorful, add a splash of water or sauce before reheating, and cover it to prevent drying out.