Mushroom Shepherd’s Pie

I’ve been trying to eat vegetarian meals more often, partly as a cost-saving measure and partly as a way to fill this temple with more vegetables and less flesh. This is one of my favorite “substitution” dishes so far. Normally I’m very skeptical of dishes that attempt to replace the meat in a traditionally meat-filled dish with some veg substitute. My general feeling has been that if you’re just trying to emulate the same taste, eat the damned meat. No, I’m looking for an alternative treatment that is terrific in itself, not just something that makes you say, “Yeah, this is pretty close to the real thing.”

This is based on a Vegetarian Times recipe that Dad sent me ages ago. I made some modifications.

Mushroom and Caramelized Onion Shepherd’s Pie


  • 1.5 lb. Yellow Finn or Yukon gold potatoes, peeled and quartered
  • 3/4 c lowfat milk
  • 4 Tbs. unsalted butter, divided
  • 3 Tbs. olive oil, divided
  • 2 medium yellow onions, halved and sliced (3 cups)
  • 2 Tsps. sugar
  • 3 medium portobello mushroom caps
  • 1½ lb. button mushrooms, sliced (I used the presliced ones – lazy!)
  • 2 cloves garlic, minced (2 tsp.)
  • 1 cup grated Asiago cheese


  1. Preheat the oven to 375.
  2. Toss the potatoes in a pot and cover them with water. Boil for 30 minutes. Save a cup and a half of the water so you can make bread this weekend (if you’re doing that, use 2lbs of potatoes – you need an extra cup of mashed potatoes for that recipe).
  3. While the potatoes are boiling, slice the onions and fry them in a non-nonstick pan with 2T butter and 1T oil, and the sugar. You’re going for golden brown here, and it will take about 20 minutes. Keep an eye on them. You’ll want to stir them occasionally, but don’t hassle them. Once the start to brown, don’t abandon them, because they can go from “golden” to burned really fast. Set them aside when they’re done.
  4.  While all of the above is going on (so you’ve got the potatoes in the pot, and the onions have just started but don’t need your attention yet), put the portobellos “gill side” up on a baking sheet and drizzle a little olive oil on them. Put them in the oven for about 25 minutes (see how the timings all work here?). When they’re done, slice them into long strips.
  5. Toss your sliced mushrooms with the rest of the oil, garlic, salt, and pepper, and put them on another pan. Put that in the oven too. They’ll be done at the same time as the portobellos.
  6. Drain the potatoes and mash them with the milk and the last 2T butter. I ended up using quite a lot of milk. Don’t forget to add salt and pepper.
  7. When the mushrooms are done, toss the sliced mushrooms with about a half cup of the Asiago. Set them aside.
  8. In a springform pan (this worked best for me – you could do any deep casserole dish you like),  spread the portobello strips out on the bottom of the pan to make a nice base for everything else. Next, spread the mushroom and Asiago mixture on, then the onions on top of that. Spread as much of the mashed potatoes as you like on top to cover and seal everything in. The original recipe calls for 3lbs, and I ended up with a ton of leftovers, so if you follow the weights I mentioned in this recipe, you should be fine. Now sprinkle the rest of the Asiago on top.
  9. Toss this in the oven and bake for 40 minutes. I discovered that my springform isn’t leakproof anymore! Put some foil under it just in case. At about the 30 minute mark, you may also need to lay some foil on top of the whole thing to keep the cheese from burning.
  10. Yum.