Some dinners just feel like a full meal the second you pull them out of the oven, and this Mushroom Lentil Shepherd’s Pie is exactly that.
It’s hearty, packed with vegetables, and layered with creamy mashed potatoes that turn lightly golden on top.
The filling is made with mushrooms, lentils, carrots, celery, and herbs, giving it a rich, savory flavor that doesn’t need meat to feel satisfying.
It serves 6, makes great leftovers, and freezes well for busy weeks. Simple ingredients, one big pan, and a comforting dinner that works just as well for Sunday night as it does for meal prep.
Why You’ll Love This Recipe
It feeds 6 people, which makes it great for a large family dinner without doubling ingredients.
The prep time is only about 10 minutes, and most of the cooking happens on the stove and in the oven while you do something else.
It’s completely vegetarian but still filling thanks to lentils and mushrooms, so you don’t feel like anything is missing.
It works well for meal prep since it reheats beautifully and can be frozen in portions for later.
Ingredients You’ll Need
This recipe is made in two simple parts: mashed potatoes and a hearty vegetable filling.
For the mashed potatoes:
3 pounds russet potatoes, peeled and diced
1/3 cup milk
2 teaspoons salt, divided
1/2 teaspoon ground black pepper
For the filling:
2 tablespoons olive oil
1 1/2 pounds mushrooms, sliced (button or crimini)
1 medium yellow onion, diced
1 large carrot, peeled and diced
1 rib celery, diced
2 cloves garlic, minced
1/2 cup green or brown lentils
2 tablespoons tomato paste
1 tablespoon soy sauce (or tamari for gluten free)
2 teaspoons Dijon mustard
1 teaspoon dried thyme
1 teaspoon dried rosemary
1/2 teaspoon ground black pepper
1 cup broth
2 cups frozen peas
For serving (optional):
Fresh ground black pepper
Nutritional yeast
Fresh parsley
How to Make Mushroom Lentil Shepherd’s Pie
- Cook the potatoes.
Bring a large pot of salted water to a boil. Add the peeled and diced potatoes and cook until fork tender. Reserve 1 cup of the starchy cooking water, then drain the rest. Mash the potatoes with milk, ½ teaspoon salt, pepper, and some of the reserved water until smooth. Set aside. - Prep the vegetables.
Dice the onion, carrot, and celery. Mince the garlic. Clean and slice the mushrooms. - Cook the filling base.
Preheat the oven to 375°F (190°C). In a large oven-safe pan or skillet, heat olive oil over medium-high heat. Add the onion and cook for 4–6 minutes until soft. Add the mushrooms and cook until reduced and tender, about 5 minutes. - Add vegetables and seasonings.
Reduce heat to medium. Stir in the carrot, celery, and garlic. Cook for 3–5 minutes until slightly softened. Remove from heat and stir in lentils, tomato paste, Dijon mustard, thyme, rosemary, and black pepper. - Add liquid and peas.
Pour in the broth and soy sauce. Stir well to combine. Scatter the frozen peas evenly over the top of the filling. - Assemble.
Spread the mashed potatoes over the peas, smoothing them out to seal in the filling. - Bake.
Bake for 40–45 minutes until the top is lightly browned and the filling is bubbling at the edges. For extra browning, broil for 2–3 minutes at the end. - Serve.
Let cool slightly before serving. Garnish with fresh parsley or black pepper if desired.
Recipe Notes
Lentils: Green or brown lentils work best because they hold their shape while baking. If using canned lentils, drain and rinse well before adding.
Salt Level: The amount of salt needed depends on the broth and soy sauce you use. After adding the broth, taste a small piece of mushroom or carrot and adjust seasoning if needed.
Soy Sauce: Soy sauce adds depth and saltiness to the filling. For a gluten free version, use tamari instead.
Mashed Potatoes: For richer mashed potatoes, you can add 2 tablespoons of butter. For a cheesy version, stir in grated parmesan or a few tablespoons of nutritional yeast.
Milk Substitution: To make the recipe fully vegan, replace the milk in the mashed potatoes with a neutral plant-based milk such as soy or cashew.
Freezing: This dish freezes well. You can freeze the whole pan or portion it into containers for easy meal prep.