I call this “slapdash” because it’s made almost entirely with things that are already cooked — it’s leftovers, essentially, whacked into a casserole and made all shiny and new.  It doesn’t have to be that way; you could certainly start the recipe by cooking up some ground lamb or beef with the onion while it’s sauteing.  But if you use leftovers, this is a resourceful and unbelievably easy way to get a second hot, healthy meal into the family with almost no extra effort.

This is what the pie looks like before you’ve browned it.

Slapdash Shepherd’s Pie

6 cups cubed cooked boneless lamb (about 1 1/2-2 lbs)
4 tablespoons unsalted butter
1 large onion, diced
4 large or 6 medium carrots, in 1/2 inch slices
2 ribs celery, thinly sliced
2 tablespoons chopped fresh rosemary
1 tsp. salt
1/2 tsp. pepper
2 tablespoons flour
1/4 cup red wine or beer
3 cups chicken or beef stock
1 1/2 cups peas (frozen is fine, and at most times of year probably better)

4 cups leftover mashed potato
2 large eggs

To assemble the shepherd’s pie, saute the onion in butter in a large skillet until softened.  Add the carrots, celery, and rosemary; cook for about 5-7 minutes, until the vegetables begin to soften slightly.  Season with salt and pepper; sprinkle with flour.  Mix until the vegetables are totally coated with the flour.  Cook for about 1-2 minutes, then add the wine or beer and stock.  Bring to a boil, reduce the heat, and simmer for another 5 minutes.  Add the cubed lamb and peas, stir to combine, and remove from the heat.
In a large bowl, beat the eggs and leftover mashed potato together until thoroughly combined.  Pour the lamb mixture into a 9×13 casserole dish, then spread the mashed potato mixture evenly over the top.  I always leave a slight border around the edges so you can see the filling beneath, but that’s entirely optional.
If you’re baking the casserole right away, put it in a 400 degree oven for 15 minutes, then turn on the broiler and broil for 3-5 minutes or until the top begins to brown.  If you’ve made it in advance and are reheating it, cover with foil and bake at 400 degrees for 30-35 minutes, then remove the foil and broil it for 3-5 minutes to get the potato topping browned.

And this is what’s underneath the potato topping.