I did fix it with a few handfuls of green peas, but that can easily be left out

I've been wanting shepherd's pie since a couple days before I started eating paleo. In fact I had bought a small bag of potatoes just to make it. I ended up finally tossing them out last week.  Here's my recipe for quite a large batch.  It filled an 11"x14" dish nearly to the top.

4lbs ground beef (75/25)
1 medium onion diced (probably could have used more)
5 carrots diced
1 cup sliced mushrooms
2 small handfuls frozen peas
1-1/2 cups beef broth
About 4 tsp arrowroot
About 1-2Tbs clarified butter
Salt and pepper to taste

Mashed potatoes (I will double this recipe next time)
1 head cauliflower
A few tsps of coconut milk
2Tbs clarified butter
Dash of salt
2 whole eggs
2 cloves garlic

Started off by steaming cauliflower and garlic then let it cool while I cooked the rest.

Browned the beef in 2 batches then added the carrots, mushrooms and onions and cooked until tender.  In another pan I melted butter over low heat.  Combine the broth and arrowroot. Then slowly whisk into the butter. I ended up straining mine because the kids held my attention too long and I ended up with starchy goo on the bottom. Add worchestershire, peas, salt, pepper and gravy to meat and veg mixture.

Process cauliflower and garlic in food processor, add butter and just enough coconut milk so it'll completely blend. Add salt and eggs. Then smooth out on top of meat mix. Texture it with a fork to help with browning. If you didn't add peas, you can probably get away with simply broiling the pie for a few minutes until brown.  I cooked mine at 350 for about 10 minutes before browning just to make sure the peas had warmed up. My kids loved it and had no idea it wasn't my usual recipe. My son kept asking for more mashed potatoes.