Preheat oven to 500F. Prep and grease two baking sheets. Lightly grease and prep a casserole dish.

Slice the zucchini, eggplants and potatoes into ½-inch slices.

Spread out the zucchini, eggplant and potatoes in a single layer across the baking sheets. Drizzle the vegetables with olive oil and sprinkle lightly with oregano, salt and black pepper.

Place baking sheets in the oven. Roast for 15 minutes, or until golden but still firm (you don't want the vegetables to fall apart as they'll keep cooking later). The eggplant will need another 5 minutes. Remove roasted vegetables from baking sheets and set aside.

Set a large pot or Dutch oven on medium heat. Add 2 tablespoons of olive oil.

Add the onions and saute until softened, about 2-3 minutes.

Add garlic, and saute for another 1 minute.

Add cooked lentils, diced tomatoes, 1 tablespoon dried oregano or double fresh, chilli flakes and ½ teaspoon salt and ¼ teaspoon black pepper to the pan.

Cook lentils in tomato sauce for 10-12 minutes, stirring often, until reduced and thickened.

Add butter to a small saucepan. Whisk in flour and cook, stirring constantly with a spatula or a wooden spoon, until a paste forms.

Cook for about 1-2 minutes on low-medium heat - watch so that the flour paste doesn't brown, as it will overcook.

Add hot milk, continuing to whisk constantly as the sauce thickens. Bring gluten free bechamel sauce to a boil. Season with salt and pepper and cook, whisking constantly, for 2 to 3 minutes.

Whisk the eggs in a medium bowl. To finish the gluten free bechamel sauce with eggs, take out a small amount of the sauce and add it to the whisked eggs; stir to combine. Pour the eggs into the gluten free bechamel sauce and let it cook for another 1-2 minutes. Remove gluten free bechamel sauce from heat.

Assemble Vegetarian Moussaka in a 9 x 13 baking dish.

First, pour ½ cup of the lentil sauce on the bottom of the baking dish and spread.

Layer the eggplants on top. Then follow with a layer each of zucchini and potatoes. Sprinkle with half the feta cheese. Add the remainder of the lentil sauce. Repeat the vegetables in the same order.

Finally, pour bechamel sauce on top, and smooth it out with a spatula. Top with remaining feta and parmesan. Sprinkle with oregano.

Cover gluten free Greek moussaka with foil without touching the top of the casserole (if this isn't possible, skip the foil).

Bake at 375F for 45 minutes. In the last five minutes, switch to broil to brown the cheese.

Serve hot for best results. However, Greek moussaka will slice more neatly after it has had time to cool - so if you are looking for neat slices, cut it out of the refrigerator, then reheat the slices individually.