Shepherd's Pie

4-5 russet potatoes, peeled and cut into pieces
1/2 tsp. salt
1/4 tsp. pepper
1/4-1/2 c. milk
1 egg
4 Tbs. butter

2 Tbs. butter
2 carrots peeled and chopped
1 onion, diced
1 1/2 lbs. ground beef
4 Tbs. tomato paste
1 tsp. minced garlic
1/2 tsp. ground thyme
4 Tbs. flour
2 1/2 c. chicken broth (I like to add 1 extra bouillon cube)
1 Tbs. Worcestershire sauce
1/2 c. peas

1.  Boil potatoes until fork tender, 10-15 minutes.  Drain and return to empty pan.  Add 4 Tbs. butter, salt, pepper.  Whisk milk and egg together.  Pour the milk/egg into potatoes while mashing.  Add more salt/pepper/milk if needed.

2.  While potatoes are cooking, heat cast iron skillet over medium heat.  Melt 2 Tbs. butter in skillet, then add carrots and onion.  Cook until softened, about 5 minutes.  Add ground beef and cook, breaking meat into small pieces.  Cook meat through.

3.  Stir in tomato paste, garlic, and thyme. Stir in flour and cook for 1 minute.  Add broth and Worcestershire sauce, stir and cook until mixture thickens slightly, 5-10 minutes.  Turn off heat, add peas, corn, and more salt/pepper if needed.

4.  Top meat mixture with mashed potatoes.

5.  Adjust oven rack closer to the broiler, I just raise it to the middle-top rack.  Broil on low until the potatoes are golden brown and crusty, 5-10 minutes.  Remove from oven and let cool 10 minutes before serving.