Preheat your oven to 375°F and line a 9x5 loaf pan with parchment paper.
Heat the olive oil in a large skillet over medium. Then, add the onions, mushrooms, carrots, celery, garlic, and bouillon. Stir occasionally until tender, about 8-10 minutes.
In a large food processor, pulse together the cooked veggies, lentils (leave out ½ cup), flaxseed, liquid aminos, walnuts, oat flour, bread crumbs, thyme, oregano, smoked paprika, salt, pepper, and liquid smoke (optional).
Pulse until the mixture starts to stick together when you press it between your fingers. For the best texture, don't overmix. Transfer mixture to a large mixing bowl and stir in the rest of the lentils.
Then, pack the lentil mixture firmly into your parchment-lined pan. Stir the glaze ingredients together in a bowl and brush evenly on top of the loaf.
Bake uncovered at 375°F for 40-45 minutes, or until the glaze appears matte. Let the loaf cool in the pan for 10-15 minutes, then use the parchment paper to lift it out of the pan. Slice and serve warm.