Preheat the oven to 375°F (190°C) and grease the baking dish.

Boil salted water and cook lasagna noodles according to package instructions until al dente.

Sauté onions and garlic over medium heat in olive oil until translucent.

Add mixed vegetables to the skillet and sauté until softened.

In a mixing bowl, combine sautéed vegetables, cooked sausage, and ricotta cheese.

Spread filling on the bottom edge of each noodle and roll them up tightly.

Place the rolled noodles seam-side down in the greased baking dish.

Pour marinara sauce over the roll-ups and sprinkle with mozzarella cheese.

Bake for 25-30 minutes until cheese is bubbly and golden brown.

Let cool for 5-10 minutes before serving warm.