1.	Preheat oven to 400 degrees F.
2.	In a large saucepot, cover potatoes with salted water by 1 inch; bring to a boil.
3.	Reduce heat; simmer until fork-tender, 15 to 20 minutes. Drain.
4.	Heat a large skillet over high heat. In two batches, cook ground beef until no longer pink, about 5 minutes per batch.
5.	Transfer beef to a colander set in a bowl; let fat drain off and discard fat.
6.	Add ¼ cup water to the skillet, scraping up browned bits (deglazing the fond) with a wooden spoon.
7.	Reduce heat to medium; add onion and carrots. Cook, stirring occasionally, until softened, about 5 minutes.
8.	Stir in tomato paste. Add flour; cook, stirring, 2 minutes.
9.	Add Worcestershire sauce, 1 cup water, and beef. Season with 1 teaspoon salt and ¼ teaspoon pepper. Simmer until thickened, stirring occasionally, about 10 minutes.
10.	Stir in peas; cook 1 minute.
11.	Add filling to a 9-inch pie dish.
12.	In large saucepot, bring milk and butter to a simmer; remove from heat.
13.	Return potatoes to the saucepot and mash. Season with 2 teaspoons salt and ¼ teaspoon pepper.
14.	Spread potato mixture over the pie; use a fork to make peaks.
15.	Bake on a baking sheet until top is browned, 25 to 30 minutes. Cool slightly; serve. 
Deglaze- to swirl or stir a liquid (usually wine or stock) in a pan to dissolve cooked food particles remaining on the bottom.  The resulting mixture often becomes the base for a stock
Fond- French for “bottom”.  Fond refers to the concentrated juices, drippings, and bits of food left in pans after foods are roasted or sautéed.