Preheat oven to 400 degrees and roast portobello mushrooms for 20 minutes. Set aside to cool. Reduce oven heat to 350 degrees.

In a large skillet on medium heat, add olive oil and saute onion and yellow bell pepper until translucent in color. Add minced garlic, stir and cook for another 1 or 2 minutes.

Turn heat to low and add 3 cans of tomato sauce. Add salt, pepper, oregano and red pepper flakes. Simmer for one full hour with the lid on.

Boil brown rice lasagna noodles in salted water for amount of time listed on the directions. Lay out cooked noodles in a single layer on a bake pan or parchment paper. Do not overlap noodles or they will stick and fall apart upon seperation.

Finely slice roasted portobello mushrooms and set aside. Finely slice 2 raw zucchini and set aside.

In a large bake dish spread one thin layer of tomato sauce on the bottom. Lay down 3 noodles down on top of sauce and cover with first layer of shredded vegan mozzarella cheese.

Next layer starts with another 3 noodles. Spread another layer of tomato sauce and add a layer of your roasted portobello mushrooms. Top with more tomato sauce.