Preheat oven to 350 degrees Fahrenheit.
In a large saucepan over medium heat, add olive oil and diced onion, celery and bell peppers. Sauté for 5 minutes.
Add spices (besides paprika) and diced mushrooms. Sauté for 5 more minutes.
Split can of tomatoes keeping half in dish and half in can.
In a food processor, add orange juice, half of tomatoes, brown sugar, paprika and 1 tablespoon liquid aminos. Process until smooth. Set aside.
Using food processor again, add oats, other half of tomatoes, ground flax seed and 1 tablespoon liquid aminos. Process to form a crumbly mixture. Add in lentils, bread crumbs and sautéed veggies and process again to form smoother mixture.
Add mixture to loaf pan, press down and bake for one hour.
Take out and top with tomato sauce mixture. Put back into oven and bake for 15 more minutes.
Allow loaf to set and cool for 15 minutes before removing. Slice and enjoy!