Rutabaga and Lentil Cottage Pie

From the garden

• 2 lb rutabaga, peeled and cut into 1-inch cubes
• 1 lb potatoes, peeled and cut into chunks
• 1 medium yellow onion, diced
• 2 medium carrots, diced
• 3 cloves garlic, minced
• 4 sprigs fresh thyme, leaves stripped
• 1 cup peas (fresh or frozen)

From the pantry

• 1 cup brown or green lentils, rinsed and picked over
• 8 oz mushrooms, sliced · they do the savory work the meat used to
• 2 tbsp tomato paste
• 1 tbsp soy sauce
• 3 cups vegetable stock
• 1 bay leaf
• 5 tbsp olive oil · divided between the filling and the mash
• salt · to taste
• black pepper

1. Boil the rutabaga in well-salted water for 5 minutes, then add the potatoes and cook 20–25 minutes more, until a knife slides through both without resistance. Rutabaga is far denser than potato and needs the head start.
2. Warm 2 tablespoons of the oil in a wide, deep skillet meanwhile and cook the onion, carrots, and mushrooms with a pinch of salt until browned and the mushroom liquid has cooked away, about 10 minutes. Add the garlic and thyme for the last minute.
3. Stir in the tomato paste and cook 1 minute until it darkens, then add the lentils, stock, soy sauce, and bay leaf. Simmer uncovered 25–30 minutes, until the lentils are tender and the pan is saucy rather than soupy.
4. Drain the roots and let them steam dry in the colander a minute, then mash with the remaining 3 tablespoons of oil, salt, and pepper. Leave the mash a little coarse; rutabaga carries more water than potato and a rough surface browns better.
5. Heat the oven to 400°F. Stir the peas into the lentils, fish out the bay leaf, taste for salt, and spread the mash over the top, roughing up the surface with a fork so it catches the heat.
6. Bake 25–30 minutes, until the filling bubbles at the edges and the peaks are well browned. Rest 10 minutes before serving so the filling sets enough to hold a spoonful.