Mushroom lentil shepherd pie

This shepherd pie has a moist lentil and mushroom filling under a soft potato topping. Reserved lentil cooking liquid keeps the filling moist without a separate gravy. The oven stage heats the layers together and colors the ridges in the mash, so most of the cooking happens before the pie is assembled.

Build a filling that holds its shape

Cook the lentils until tender before draining, and reserve the measured cooking liquid first. It is easy to pour that useful liquid away once the colander is in the sink. The filling needs enough moisture to stay soft under the potatoes, but a very wet base will make clean portions harder to lift.

Finely chop the mushrooms so they mix through the lentils rather than forming a separate layer of slices. Let the onion, carrot and mushrooms cook until the pan has lost most of its loose mushroom liquid. If the vegetables are crowded, this can take longer than the stated time. Stir across the bottom and watch for the change from a watery pan to vegetables that can be moved aside without liquid immediately flooding the gap.

Add the tomato paste and thyme after that moisture has reduced. Stir them through the vegetables before returning the lentils and reserved liquid to the pan. The mixture should be moist enough to spoon, with no deep pool around its edges.

Make the potato topping easy to spread

Cut the potatoes into similar pieces so they soften together. Drain them thoroughly and mash with the measured soy milk, oil and salt. Use unsweetened milk; a flavored drink can carry its sweetness through the whole topping.

A hand masher gives you control over the texture without needing completely smooth potatoes. Spoon the mash in several small heaps over the hot filling, then join those heaps gently with the back of a spoon. Trying to drag one large mound across the pan can pull the lentils up into the topping.

Roughen the surface with a fork after it is covered. The small ridges provide exposed edges that can color in the oven. Rest the baked pie briefly before serving so the filling is easier to portion.

Assemble ahead with the center in mind

Use a baking dish if your skillet is not ovenproof, transferring the filling while it is hot. For planned leftovers, portion and refrigerate promptly in shallow containers rather than cooling the whole deep skillet on the counter.

A pie baked from chilled will need longer than one assembled from hot components. Check the center as well as the bubbling edges. USDA recommends reheating leftovers to 165°F / about 74°C throughout. Keep to the card’s three-day refrigerated storage limit.