Step 1

Preheat the broiler to high.

Step 2

Trim and chop lamb into bite sized pieces and place in a medium sized mixing bowl. Add 1/2 tsp of salt, 1/4 tsp of black pepper, and worcestershire sauce. Toss to combine and set aside.

Step 3

Place chopped potatoes in a medium sized pot. Fill with cold water and cover with a lid. Bring to a boil over high heat, then drop the heat to medium high and simmer uncovered for 15 - 20 minutes or until potatoes are fork tender.

Step 4

While potatoes are cooking, heat a large dutch oven over medium heat. Add olive oil and heat an additional 1 - 2 minutes.

Step 5

Stir in onions and carrots along with 1/2 tsp of salt. Cook 12 - 15 minutes, stirring occasionally, until carrots and onion have softened.

Step 6

Add the garlic and cook 1 minute longer.

Step 7

Remove the vegetables from the pan and place in a medium sized mixing bowl. Increase the heat to medium-high.

Step 8

Reserving the marinade, add the lamb to the dutch oven. Brown the lamb on all sides.

Step 9

Place the cooked lamb in the bowl with the vegetables and drop the heat back to medium.

Step 10

Mix the red wine with the reserved marinade and add to the dutch oven.

Step 11

Using a whisk, scrape the bottom of the pan to remove all the tasty brown bits.

Step 12

Continue to cook over medium until the wine is reduced by half.

Step 13

Add 2 tablespoons of butter to the red wine. Swirl to melt then whisk in the flour. Cook the wine, butter, flour mixture for 2 - 3 minutes, stirring constantly.

Step 14

Slowly pour the beef stock into the wine, butter and flour, whisking constantly until smooth. Bring it to a simmer and allow to cook for 3 minutes longer to thicken.

Step 15

Carefully add the lamb and vegetables back into the gravy. Add the tarragon, 1/4 teaspoon of pepper, and peas. Taste and adjust the salt if needed.

Step 16

Keep mixture warm over a low flame while making the mashed potatoes.

Step 17

Mash the potatoes using a hand masher or stand mixer. Add in the milk, half & half, 4 tablespoons of butter, and 1/4 teaspoon of salt.

Step 18

If broiling in a glass casserole dish, transfer the lamb and vegetable mixture to the bottom of the casserole dish. If broiling in the dutch oven, scrape down the sides of the pan with a spatula to prevent burning.

Step 19

Cover the lamb and vegetable mixture with the mashed potatoes, smoothing out the top as best you can.

Step 20

Place the pie, uncovered, under the broiler for 8 - 10 minutes or until the potatoes brown. I check mine at 5 minutes and rotate the pan to prevent burning.

Step 21

Allow to cool 5 - 10 minutes prior to serving.