Rinse the lentils and then combine them with the vegetable broth in a medium-size pot over high heat. Bring to a boil and then reduce heat to low and simmer for about 30 minutes. Once they are tender drain them and then set aside in a large bowl.Next preheat the oven to 375°F and line two loaf pans with parchment paper. (If you only have one loaf pan, you can cook each loaf one at a time or half the recipe.) Combine the ground chia seed (or flax) with water and then set aside to thicken.Using a food processor, finely chop the onion, garlic, mushroom and pepper by pulsing a few times. Warm about 2 tablespoons olive oil in a large skillet over medium-heat and then add the onion. Sprinkle with salt & pepper then cook for 2-3 minutes, until translucent. Add the mushrooms, garlic, carrot and green pepper then cook for about 10 minutes. Remove from heat and set aside.Using the food processor again, mash half of the lentils by pulsing a few times. Add them back to the bowl along with the remaining lentils and sautéed vegetables.Process the remaining ingredients to finely chop (oats for oat flour, bread for breadcrumbs, walnuts and sunflower seeds) then add them to the bowl along with the herbs.Mix the Worcestershire and the tomato paste into the chia seed mixture and then add to the bowl. Stir everything together until the liquid is evenly distributed. Pour half of the mixture into each loaf pan then smooth it down with a spatula (or the back of the spoon) to create the shape of a loaf.Lastly, combine the ingredients for the balsamic glaze in a small bowl and mix together. Spread it over the top of each loaf then cook in the oven for 40-45 minutes. Allow to cool for about 10-15 minutes before serving.