The blend of firm and well seasoned Puy lentils with vegetables in a tomato base is surprisingly comforting, and lends itself to re-invention. For the filling, you could substitute half of the lentils with beef or lamb mince, and play around with different types of veggies you may have on hand. Parsnips, finely minced cabbage, even eggplant could work in the filling.
You may even want to play around with the topping, replacing half the potatoes with cauliflower mash. To make this dish truly vegetarian you would also remove the Parmigiano-Reggiano and replace w vegetarian Parmesan.
For the Topping:
6 medium sized russet potatoes
1 1/2 tablespoons salt
2 tablespoons butter
1/4 cup milk
1/2 cup Parmesan cheese
1/2 cup Cheddar cheese
For the Filling:
1 cup du Puy Lentils
1/2 tsp thyme
1 1/2 tsp sea salt
1 onion finely chopped
4 cloves garlic minced
1 cup chopped tomatoes (canned)
2 tablespoons olive oil
1 cup sliced mushrooms (any type)
1 large carrot
Boil potatoes in salted water until fork tender. Drain and allow to cool.
Add salt, butter, milk, cheese and mash until smooth. Adjust seasoning.
Make filling. Add lentils to a pot and cover with 3 cups water (or broth), and salt. Simmer on low for 20 mins.
While lentils cook, start the vegetables. Add olive oil to skillet and add chopped onion and garlic. Cook for 3 minutes until onions soften.
Add chopped tomatoes to the onions, then add thyme, carrots, parsnips, and mushrooms. Allow to simmer in pan for 10 minutes.
When mushrooms have softened, add the lentils.
Add the filling ingredients to an oven safe casserole dish, and top with mashed potato mixture. Bake at 350 F (175 C) for 30 minutes or until pie has browned and is bubbling.