This was adapted from a Samantha Seneviratne recipe in NYTimes Cooking. It may be sacrilege to call it a Shepherd’s Pie because of it’s lack of meat, but it was delicious. We used a combination of lentils and mushrooms to fill out the filling and we have gratefully embraced Samantha’s way of mashing the potatoes. Don’t be shy on the fresh herbs or the seasoning.
For this you’ll need: x4 large russet potatoes (peeled and quartered), 1 cup dry lentils, 6-8 Tbsp unsalted butter, 1/2 cup heavy cream, 1 cup sharp white cheddar (grated), 1 yellow onion (chopped), 2 medium carrots (peeled and diced), 4 cloves garlic (crushed and chopped), fresh thyme, fresh rosemary (4-5 sprigs each, at least), 3 cups mushrooms (we used a mix of oyster and shiitake; sliced), 1/3 cup tomato paste, 1 to 5 cups vegetable stock (this depends on whether you cook the lentils in stock or not), 3 Tbsp flour, salt and pepper.
Preheat the oven to 375 and start a large pot of water on to boil.
In a separate pot, cover the dry lentils in water or stock so that there’s several inches covering the dry lentils. Place this over high heat until boiling, reduce heat to a simmer and cook for about 15 – 20 mins until just tender. Remove from heat and drain.
Place the peeled and quartered potatoes into the boiling water, return to a boil, reduce heat to a gentle bubble and cook until tender – about 15-20 mins. A fork should easily pass into them. While these are boiling, place x4 Tbsp of butter and the cream into a small pot over low heat. Add some fresh thyme by scraping the leaves from the stem with your fingers. Heat until the butter is melted but don’t let it bowl. Remove from heat.
Once the potatoes are boiled enough, drain the water and put the potatoes back into the pot. Mash them with a potato masher until well broken up (but not necessarily smooth). Stir the butter/cream/thyme and the grated cheese (saving a little bit for the topping) into the mashed potatoes using a wooden spoon until smooth. Add salt and pepper and combine well.
In a cast iron skillet or other oven safe pan, melt x2 Tbsp butter over medium heat (you may want to have a few more pads of butter on hand to add in later if the mixture starts to dry and stick). Add the chopped onion, carrot and garlic and stir together. Scrape off the leaves of a few thyme and rosemary sprigs with your fingers and stir these in as well. Cook over medium heat until onion turns soft and slightly opaque – 5-10 mins.
Add another x2 Tbsp butter and the chopped mushrooms into the carrot/onion mixture and stir together well. Allow this to cook until the mushrooms are just beginning to brown – about 10 mins. Add in the cooked lentils, tomato paste and a good grinding of salt and pepper and stir together well. Allow to cook for a further 2-5 mins until the tomato paste is spread throughout.
Add the stock to the mushroom/lentil mixture, stir together well, and sprinkle the flour over the top. Stir again and allow to cook over medium heat until the sauce has thickened and reduced – about 10 mins.
Remove from the heat and gently spread the mashed potatoes over the top to create a “crust.” Add the remaining grated cheese over the top of the potato crust. Place a baking tray on the bottom shelf of the oven and then place the skillet on top of the tray to catch any drippings. Bake for 30 mins until bubbling and browning.
Remove from oven and let stand for about 10 mins to settle and cool.