Start by preheating your oven to 375°F so it's fully hot by the time you're ready to bake. While it heats, generously grease every cup of your muffin tin with oil or cooking spray. This step matters more than you'd think, since wonton wrappers can stick stubbornly if the tin isn't well coated.
In a large skillet, brown the ground beef over medium heat until no pink remains, then drain off the excess fat. Stir in the marinara sauce, garlic powder, and Italian seasoning, letting everything simmer together for a few minutes. This gives you a rich, well-seasoned meat sauce instead of two separate flavors fighting for attention.
In a bowl, whisk together the ricotta cheese, egg, and Parmesan until smooth and well combined. The egg is what keeps this mixture from turning watery once it bakes. I like to season this layer lightly too, since ricotta on its own can taste a little flat.
Press one wonton wrapper into each greased muffin cup, pushing it gently down into the bottom and up the sides. Don't worry if the corners stick up a little; that's exactly what gives these cups their pretty, ruffled edges once baked.
Add a spoonful of the ricotta mixture first, followed by a spoonful of the meat sauce, then a sprinkle of mozzarella. Repeat with a second wonton wrapper rotated slightly, and top it again with ricotta, sauce, and cheese. This layering is what gives every bite that classic lasagna taste.
Slide the muffin tin into your preheated oven and bake for 18 to 22 minutes, until the cheese is melted and the wrapper edges turn golden brown. If the edges brown too quickly, loosely tent the pan with foil for the last few minutes.
Let the lasagna cups rest in the tin for about 5 minutes before removing them; this helps them hold together instead of falling apart. Run a small knife around the edges to loosen them, then lift each one out gently and finish with a sprinkle of fresh parsley.