In a large skillet or saucepan, heat the olive oil over medium heat. Add the onion and cook until softened, about 5 minutes. Add the garlic and cook for another minute until fragrant.
Add the ground venison to the skillet. Cook for 8-10 minutes, breaking it apart with a spoon, until it’s browned and fully cooked. Season with salt, pepper, and red pepper flakes, if desired.
Stir in the crushed tomatoes, tomato sauce, tomato paste, basil, oregano, thyme, and rosemary. Allow the sauce to simmer for 20-30 minutes, stirring occasionally to let the flavors meld.
In a medium bowl, combine the ricotta cheese, beaten egg, 1 cup of shredded mozzarella, and the Parmesan cheese. Mix until well-blended. Set aside.
Preheat your oven to 375°F (190°C). Spread a thin layer of the venison meat sauce on the bottom of a 9x13-inch baking dish.
Layer with 3-4 cooked lasagna noodles, then add a layer of the ricotta cheese mixture and another layer of the meat sauce.
Repeat the layers (noodles, cheese, meat sauce) until you’ve used all the ingredients, ending with a final layer of meat sauce on top. Sprinkle the remaining 1 cup of shredded mozzarella on top.
Cover the baking dish with aluminum foil and bake for 25-30 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese on top is melted and golden brown.
Let the lasagna cool for about 10 minutes before slicing. Garnish with fresh basil or parsley if desired.
Slice into portions and serve your venison lasagna hot. Enjoy with a side salad, garlic bread, or a glass of red wine for a truly comforting meal!