Preheat oven to 350F.
In a small blender with grind attachment, food processor or a spice grinder, add lentils and grind to a flour. (I use my Magic Bullet with the flat blade, it's okay to have a few whole lentils as the red variety are quick cooking).
Add the lentil flour along with the ingredients veggie pulp through seasonings, and stir well to combine.
Blend the tomato along with 1/4 cup water in a blender or food processor. Next, add enough water to have 1 cup of liquid. Stir in the apple cider vinegar. Add the liquid to the lentil mixture and stir for 30 seconds to a minute to incorporate well. It should resemble a thick but pourable pancake batter after it sits (the flax and lentils will start absorbing the water the longer it sits).
Then add the oil to a 9 inch springform pan** and place in the oven to warm (about 2 minutes).
Pour batter into the pan and spread with a spatula. Bake for 25-28 minutes until the bread is firm to touch.
Let cool slightly, cut and enjoy plain while warm OR spread with tomato paste mixture or marinara and sprinkle with shredded cheese and return to oven until cheese is melted, about 3-4 minutes (my preference).