• Place the potato chunks in a saucepan and cover them in water. Boil the potatoes until tender. Or, you can place them in the steamer basket in your Instant Pot with 1 cup of water at the bottom and cook on high pressure for 6 minutes with QUICK RELEASE (my preferred method). Drain water off, add potatoes to a large mixing bowl with the soy milk and nutritional yeast flakes (if using), salt and pepper to taste. Mash by hand or blend with a hand blender until smooth. Set aside.
• Preheat oven to 350 degrees.

Gravy Mixture:

• Whisk the veggie broth together with the garlic powder, soy sauce, cornstarch, and salt and pepper to taste. Set aside.

Filling:

• In a large skillet, add the chopped shallots and mushrooms. Cook over medium high heat until the moisture in the mushrooms is release and then evaporated. Add the frozen veggies and cook for about 5 minutes or until all of the moisture is released and cooked out. Add the black lentils and cook for one additional minute. Stir in the rosemary.

Assembling the Shepherd's Pie

• Add the gravy mixture to the veggies in the skillet and thicken over medium-high heat. Move the mixture to the bottom of your deep-dish pie plate or square casserole dish. Top with the mashed potatoes.
  
• Bake in the oven (uncovered) for 30 minutes or until the mixture under the potatoes is bubbling and the potatoes get lightly golden on top.