Shepard's Pie

I've never made this dish before, but occasionally I crave it, therefore I wanted to find a keeper recipe. This one fits the bill for now. It's simple, not too fussy. I think I skipped the paprika and parsley garnish for extra simplicity.
Sheppard

Ingredients:

2 pounds potatoes, such as russet, peeled and cubed
2 tbsp sour cream, or softened cream cheese
1 egg yolk
1/2 cup milk or cream
salt and pepper
1 tbsp olive oil
1 3/4 lbs ground beef
1 carrot, peeled and chopped into circles
1 onion, chopped
2 tbsp butter
2 tbsp flour
1 cup beef broth
2 tsp Worcestershire
1/2 cup frozen peas
1 tsp paprika
2 tbsp fresh parsley leaves, chopped

Directions:

1. Boil potatoes in salted water until tender. Drain potatoes and pour them into a bowl. Combine sour cream, egg yolk and cream. Add the cream mixture into potatoes and mash until potatoes are almost smooth.
2. While potatoes boil, preheat a large skillet over medium high heat. Add oil to hot pan with beef. Season meat with salt and pepper. Brown and crumble meat for 3 or 4 minutes.
3. Add chopped carrot and onion to the meat. Cook veggies with meat 5 minutes, stirring frequently.
4. In a second small skillet over medium heat cook butter and flour together 2 minutes. Whisk in broth and Worcestershire sauce. Thicken gravy 1 minute. Add gravy to meat and vegetables.
5. Stir in peas.
6. Preheat broiler to high.
7. Fill a small rectangular casserole with meat and vegetable mixture. Spoon potatoes over meat evenly. Top potatoes with paprika and broil 6 to 8 inches from the heat until potatoes are evenly browned. Top casserole dish with chopped parsley and serve.

Inspiration: Rachel Ray's 30 Minute Meals from the Food Network web site.