I personally can't eat stupid "diet" food that personal trainers are always telling you to eat, like plain steamed vegetables with poached fish; I'd almost rather just be fat and die young. Get a registered dietitian if you want food advice, gym rats are not famous for their love of fine dining. Anyone who would drink a protein shake more than once is unqualified to tell you how to eat healthy food that is also delicious.
We could all use some extra comfort, especially when trying to lose fat/weight, and this works for me. The reason I am using celery root here instead of traditional potatoes is not just because it's only 8 calories per ounce mashed, it's because it stays moister and therefore needs hardly any added butter in order to actually taste buttery. (You know how you can put a ton of butter into potatoes and they can still have a dry texture? That won't happen here.) By the way, if you're not sure what a celery root looks like, I have a picture on this recipe: Cream Baked Eggs and Fried Celery Root
1 pound of lean ground beef, 93% lean or better (please don't use turkey, we are already substituting for potatoes, and if you take out the red meat too, well it's just not Shepherd's pie anymore)
1 large carrot, grated
1 small package of mushrooms, quartered, your favorite kind (if you hate mushrooms, substitute with a grated summer squash, but squeeze the juice out of the gratings.)
1/2 small onion, chopped finely
2 teaspoons salt
1 teaspoon pepper
1 teaspoon thyme
1 teaspoon savory
1or 2 tablespoons steak sauce like A-1 or HP
1 large or two small celery roots (also called celeriac) peeled (like you would peel a pineapple) and cubed
2 teaspoons of butter (yes, only teaspoons)
splash of milk (about 1/8 cup)
1 ounce grated cheese, any kind- I went trashy and used strips of one and 3/4 slices of Kraft Cheddar)
Put the peeled and cubed celery root pieces into a pot of simmering salted water and cook for about 15 minutes, or until the cubes are soft. Drain the celery root and mash up with the butter, the splash of low fat milk and some of the salt. You want about 20 ounces of this mash for your pie. Don't be cheap with the salt unless your doctor ordered you too. Dieting is not the time to cut everything out, it makes you too sad.
Saute the ground beef and onions on high heat for about five minutes until the meat is all browned. Add a teaspoon of salt, the pepper and other spices, the steak sauce, and the grated carrot and chopped mushrooms, and continue to stir and cook for a another five minutes, until everything looks heated through.
Pour the meat mixture first into a casserole dish, mine is about 11" x 8"
Top this with the celery root mash, spread it out evenly and then sprinkle the cheese on top. Bake at 375 degrees for 20-25 minutes, until the edges are brown and the cheese is melted. This makes six servings of about 175 calories each, or four very generous servings for about 265 calories per serving. With calories this low you can afford a 140 calorie bottle of Newcastle Brown Ale with it. (I'm just saying.)
You could be fancy and put fresh herbs on top, but frankly that takes away from the home-style feel in my opinion. If you go that route, I recommend dill or very finely chopped flat parsley.