Ingredients
1tbspavocado oil,or other neutral oil with high smoke point
1lbground lamb,or beef
1yellow onion,diced
1celery stalk,diced
1large carrot,diced
1clovegarlic,minced
1¼tspkosher salt
1tspdried thyme
½tspfreshly ground black pepper
1tbspWorcestershire sauce
1tbsptomato paste
1cupvegetable broth
1cupfrozen peas
2½lbsrusset potatoes,(4 medium), peeled
½cupwhole milk
Preparation
Select the Sauté setting on the Instant Pot and heat the avocado oil. Add the lamb and sauté, breaking it up with a wooden spoon or spatula, for about 7 minutes, until cooked through and no traces of pink remain.
Set a colander in a bowl. Wearing heat-resistant mitts, lift out the inner pot and pour the lamb into the colander, letting it drain. Return the inner pot to the Instant Pot housing.
Add the onion, celery, carrot, garlic, and ½ teaspoon of the salt to the pot and sauté for about 4 minutes, until the onion is translucent.
Stir in the thyme, pepper, Worcestershire, and tomato paste. Return the lamb to the pot, then add the vegetable broth and peas.
Place a tall steam rack in the pot, making sure all of its legs are resting firmly on the bottom. Place the potatoes in a single layer on the rack.
Secure the lid and set the Pressure Release to Sealing. Press the Cancel button to reset the cooking program, then select the Pressure Cook or Manual program and set the cooking time for 15 minutes at high pressure. (The pot will take about 15 minutes to come up to pressure before the cooking program begins.)
When the cooking program ends, perform a quick pressure release by moving the Pressure Release to Venting.
Using tongs, transfer the potatoes to a bowl. Add the milk and remaining ¾ teaspoon salt, then use a potato masher to mash the potatoes until smooth.
If the filling seems a little liquidy at this point, put the Instant Pot on the Sauté function and let it simmer while mashing the potatoes.
Wearing heat-resistant mitts, remove the steam rack from the pot. Stir ½ cup of the mashed potatoes into the lamb mixture in the pot. Taste both the mashed potatoes and the filling at this point, and add more salt if needed.
Transfer the lamb mixture to a broiler-safe 8-inch square baking dish, dollop the mashed potatoes on top, and spread them out with a fork, creating a surface texture.
If desired, instead of assembling and broiling the pie, simply serve the lamb mixture with the mashed potatoes on the side.
Broil the shepherd’s pie in a toaster oven (or a conventional oven) for about 5 minutes, checking often, until the potatoes are lightly browned.
Spoon the shepherd’s pie onto plates and serve immediately. Leftovers will keep for about a week in the fridge and can be warmed in a low oven or in the microwave.
