Start by heating the olive oil over medium heat in a large skillet. Add the chopped onion and sauté until it becomes translucent, about 5 minutes. Then incorporate the minced garlic and cook for just a minute until fragrant, being careful not to burn it.

Next, add the turkey sausage, breaking it apart with a wooden spoon. Cook until browned, stirring frequently. Once the meat is fully cooked, drain any excess fat. Stir in the crushed tomatoes, tomato paste, and balsamic vinegar.

Add salt, pepper, and crushed red pepper flakes as desired. Lastly, mix in half of the chopped parsley and basil. Allow the sauce to simmer for about 20 minutes on low heat, stirring occasionally.

While your sauce simmers, combine the ricotta cheese, goat cheese, whisked egg, and the remaining parsley in a bowl. Season this mixture with a pinch of salt and pepper. Stir it well until everything is evenly mixed, ensuring a creamy consistency.

Boil a large pot of salted water and cook the lasagna noodles according to package instructions until al dente. Drain the noodles and lay them flat on a clean surface or parchment paper to prevent sticking.

Preheat your oven to 375°F (190°C). In a large baking dish, start by spreading a thin layer of the sauce on the bottom. Next, on the noodles, spread a layer of the ricotta mixture, followed by layers of mozzarella and more sauce. Repeat these layers, creating a total of 3 layers, finishing with mozzarella on top and sprinkling shaved Parmesan for an extra touch.

Cover your baking dish with aluminum foil, ensuring it does not touch the cheese. Bake in the preheated oven for 30 minutes. Then uncover and bake for an additional 15-20 minutes until the top is bubbly and golden.

This step is crucial! Once out of the oven, let the lasagna sit for at least 15 minutes before slicing. This helps the layers set and makes for easier serving.