Preheat the oven to 375°F (190°C).
In a large skillet over medium-high heat, brown the ground beef with minced garlic until fully cooked; drain any excess fat.
Reduce heat to low and stir in the marinara sauce, heavy cream, oregano, salt, and pepper; simmer for 5 minutes to combine flavors.
In a small mixing bowl, combine the ricotta cheese and the beaten egg until smooth.
Spread 1/2 cup of the creamy meat sauce onto the bottom of a 9x13 inch baking dish.
Arrange 3 lasagna noodles over the sauce, followed by a layer of 1/3 of the ricotta mixture, 1/3 of the remaining meat sauce, and 1/2 cup of mozzarella cheese.
Repeat the layers twice more, finishing with the remaining mozzarella and the grated Parmesan cheese on top.
Cover the baking dish tightly with aluminum foil and bake for 25 minutes.
Remove the foil and continue baking for another 20 minutes until the top is golden brown and the sauce is bubbling.
Let the lasagna rest for 10 to 15 minutes before slicing to allow the layers to set.