Grab the ingredients, for the mashed potatoes (butter, milk, sour cream/Greek yogurt, salt, pepper, and the beaten egg), and measure everything out so it’s ready to go. Makes sure to reserve 1 tablespoon of that butter in a separate dish for later.

Add the peeled, and chopped potatoes to a medium sized sauce pan. Add cold water, just to cover, along with the 2 teaspoons of kosher salt. Cover, and allow the potatoes to come to a boil on the stove. Remove the lid, and reduce to a simmer. Allow them to simmer for 8 to 10 minutes, or until the potatoes are fork tender. Drain immediately. Allow the potatoes to sit in the colander for 2 minutes to let any excess water drip off them. then transfer the potatoes back to the sauce pan.

While the potatoes are cooking, this is the ideal time to prep all your veggies for the filling, as instructed above (the onion, garlic, mushrooms, thyme, and rosemary). Also, get the remaining ingredients measured out (tomato paste, flour, red wine, and broth). Leave the frozen veggies in the freezer until the last minute.

Returning to the cooked, and drained potatoes that have now been returned to the sauce pot they were cooked in, add the 3 tablespoons of butter, a portion of the milk, sour cream/Greek yogurt, ¾ of teaspoon of kosher salt, and the black pepper, and use a potato masher to mash until it starts getting smooth. Once half mashed, add the remaining milk and continue mashing until smooth. Then, slowly stir in the whisked egg. The potatoes should be thick, but fairly loose as they will thicken up in the oven. If needed add another tablespoon or two of milk to loosen it up more. Cover with the lid, and set aside.

At this time preheat your oven to 400 degrees Fahrenheit.

Heat a 12 inch, oven safe skillet, with high sides over medium high heat (I like to use my cast iron skillet). Note: Alternately you can cook the filling a skillet and transfer it to a separate pie dish, or casserole dish for baking. Once the pan is hot, melt 1 tablespoon of butter in the pan (omit if using a fattier ground meat), breaking up the meat into small crumbles. Season with the ½ teaspoon each of kosher salt and pepper.

Once the ground meet is mostly cooked add the onion, garlic, and mushrooms to the pan. Sauté for another 5 minutes, or until the veggies are tender. Add the thyme and rosemary and sauté for another minute, or until fragrant. Note: if you’re using a fattier meat, and there is a lot of grease, at this time, drain some of that grease off. 1 to 2 tablespoons of grease is okay, but you don’t want it to be swimming in it. Stir in the tomato paste and cook for another minute, until the tomato paste turns a darker color. Stir in the flour and cook another minute, stirring constantly.

Add the red wine and use a wooden spoon to scrape up any bits that are stuck onto the pan. Allow the wine to come to a simmer, simmer for 3 minutes. The alcohol smell should cook off (this means the alcohol has cooked off, leaving behind only the flavor), and the wine has reduced.

Add the broth, and worcestershire sauce to the pan. Allow the liquid to come to a simmer, simmer for 3 minutes, or until the liquid has thickened, and holds it’s shape for a second when you scrape a spoon through the mixture. At this time add the ¾ to 1 teaspoon of salt and pepper (each), and taste. Adjust the seasoning as needed. Stir in the frozen peas and carrots, and corn. Spread the mixture into an even layer (preparing for the mashed potatoes). If using a separate baking dish for baking the pie, transfer the filling to that dish now.

Spoon the potatoes on top of the filling, (I like to use an ice cream scoop for even distribution), and use the back of a spoon to spread them out evenly to the edges. Melt the 1 tablespoon of reserved butter and pour it on top of the potatoes.

Transfer to the oven and bake for 15 to 20 minutes, or until the filling is bubbling out on the edges.

If your potatoes didn’t get very browned then you can pop them under the broiler for 1 to 3 minutes just until the potatoes are browned, and have a slight char on the edges – keep a close eye on it.

Allow the pie to rest for 15 minutes.

If desired, garnish with chopped fresh parsley.

Use a serving spoon to scoop out portions of the shepherd’s pie onto serving plates. If serving to a crowd, I think it’s nice to put the whole pie on the table and allow guests to serve themselves. It looks nice this way, and they can easily go for seconds. We enjoy this as a hearty meal-in-one, but we also like to serve it with a simple side salad when we want to lighten the meal up a bit. (see notes for make-ahead options).

This meal re-heats great. It does lose a little bit of the sauciness, but it still tastes delicious. Allow the pie to cool completely before transferring to air tight containers. I like to use multiple Tupperware containers (or one extra large one), so that I can keep the pie in one even layer instead of mixing up the potato and filling. Store in the fridge for up to 1 week. Re-heat gently in the microwave.