Step 1. Rinse the lentils and add to a medium saucepan with the vegetable broth. Bring to a boil before reducing the heat. Simmer covered for about 30 minutes, or until just tender. Do not drain.
Step 2. Make the flax egg. Mix the flaxseed meal with 1/3 cup water in a medium bowl. Place in the refrigerator for at least 10 minutes. Preheat the oven to 350ºF.
Step 3. Heat a drizzle of olive oil or vegetable broth in a large skillet over medium-high heat. Cook the onion, carrot, celery, and garlic for about 5 minutes, or until the onion is translucent.
Step 6. In a large bowl, combine the mashed lentils, sautéed vegetables, flax egg, oats, oat flour, Worcestershire sauce. Use your hands to incorporate the ingredients.
Step 7. Make the balsamic glaze. Heat the balsamic vinegar, maple syrup, and tomato paste in a small skillet over medium high heat. Cook for about 3 minutes, or until sizzling.