1. Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius). Prepare a baking sheet lined with Gefen Parchment and spray with cooking spray.
2. In a medium frying pan, sauté the onion and garlic in one and a half tablespoons olive oil for six minutes. Add one more tablespoon of olive oil, then the mushrooms. Cook for five minutes or until mushrooms release some of their moisture. Add spinach and cook one to two minutes. Season with salt, pepper, and nutmeg. Remove from heat.
3. Place the cooked lentils in the bowl of a food processor, along with the mushroom-spinach mixture. Add eggs, seasoning, oats, and nuts. Pulse a few times. See if mixture holds together well, and if needed, add up to half a cup bread crumbs or quinoa flakes. Mix with a spoon, and then pulse again until well combined.
4. To form burgers, press mixture into a 1/3-cup greased measuring cup. Turn over onto prepared baking sheet. Drizzle olive oil over tops of burgers. Bake for 30 minutes.