Step 1

Preheat oven to 350°F.

Step 2

In a large oven-proof skillet or Dutch oven, heat three tablespoons of butter over medium heat until melted. Add the onions, garlic, carrots, and celery, and cook, stirring often, until softened, about 8 minutes.

Step 3

If making gravy specifically for this recipe: add flour to the vegetables, stir for 1 minute, then add the remaining gravy ingredients and simmer until thick.

Step 4

If using leftover gravy: add it to the cooked vegetables and mix well.

Step 5

Add one tablespoon of flour, Worcestershire sauce, wine (if using), dried thyme, and salt and pepper to taste.

Step 6

Gently stir in leftover pot roast and peas until fully incorporated.

Step 7

Top pot roast mixture with mashed potatoes. The thickness of the potatoes is to your preference.

Step 8

Brush the top of the potatoes with one tablespoon of melted butter.

Step 9

Put the cottage pie in the oven for 25 minutes, until gravy begins to bubble around the edges of the potatoes. If you want the top of the pie browner, place it under the broiler for 2-3 minutes.

Step 10

Remove cottage pie from the oven, allow it to rest for a few minutes and serve while still hot.