Preheat your oven to 180°C (350°F).
In a large skillet, sauté onions and garlic until softened.
Add mixed vegetables, lentils, tomato paste, thyme, salt, and pepper. Cook for 5-7 minutes.
In a separate bowl, combine rolled oats, chopped nuts, and vegan margarine until it forms a crumbly mixture.
Transfer the lentil and vegetable mixture into a baking dish.
Sprinkle the oat and nut topping evenly over the mixture.
Bake for 25-30 minutes or until the top is golden brown.
Serve hot.