Cook lentils in the veggie stock until quite soft (30-40 mins) You may need to add a little water. Drain any excess water before mashing.
Heat 1 tsbp of oil in a pan and saute the onion, garlic, carrot and walnuts (if using) for 5 mins until slightly softened
Stir ground flax into the 1/3 cup of applesauce. Set aside to gel for 10 mins
Mash lentils with a potato masher until about half of the lentils are mashed (you can also use a blender or food processor for this step).
Preheat oven to 350F
Stir sauteed veggies, 1 tsbp of olive oil, bread crumbs, and spices into the lentil mixture. Add the applesauce and flax mixture. Taste the mixture to adjust
Line a loaf pan with baking paper or aluminum foil. Fill the pan with the loaf mixture.
Mix the mustard, maple syrup and 1 tbsp of applesauce. Spread over the top of the lentil loaf
Bake at 350F for 60 mins. Allow to rest for 15 mins after removing from the oven before slicing
Recipe Notes
You can use water in place of the veggie stock, but then you will need to add 1/2 tsp of salt to the mixture