If you want to make this dish vegan, just substitute plain almond milk for the milk, olive oil for the butter, and omit the cheese. It's just as awesome either way.
Also, note that the filling is really whatever you want to make it. So feel free to swap out the mushrooms, beans, and corn for anything you might want more.
Prep time: 3 cocktails
2 pounds potatoes, cut into 1 1/2-inch cubes
4 TBSP butter, divided
1 1/3 cup milk, divided
4 sticks celery, chopped
1 medium onion, chopped
1/2 pound mushrooms, sliced
3 cloves garlic, minced
A few TBSP minced fresh herbs: sage, rosemary, thyme, oregano, and parsley are all great
1 1/2 TBSP arrowroot powder
1/2 can garbanzo beans, liquid drained
A handful frozen corn and/or peas
2 tsp lemon juice
A few handfuls grated extra sharp English cheddar
Salt and pepper to taste
Preheat oven to 325.
Boil the potatoes in water that is salted to taste like seawater. Once they are soft enough to be pierced with a fork easily, remove and strain water. in a medium mixing bowl, mash the potatoes with 2/3 cup of the milk and 2 TBSP butter. Add more salt, pepper, butter or milk after everything is good and mashed, if you want to adjust the seasoning. They should taste like good old fashioned mashed potatoes.
In a large frying pan, melt the remaining butter over medium heat. Add the onions and celery. Saute about 5 minutes or until the onion starts to get transparent, stirring frequently. Add the mushrooms, garlic and herbs. saute 5 more minutes. as the mushrooms cook, combine the arrowroot in a small bowl or drinking class with 3 TBSP of the milk. Whisk with a fork until the arrowroot is fully dissolved. Then pour in the rest of the milk and stir. After the mushrooms have sauted with the onion mixture for 5 minutes, add the arrowroot/milk mixture, garbanzo beans, corn/peas, lemon juice. Stir as this simmers for a couple more minutes. Salt and pepper this mixture to taste.
Now assemble your pie: In a 9x13 Pyrex pan or baking dish, pour the mushroom/onion mixture. Smooth it all out evenly with a rubber spatula, then layer the mashed potatoes over this mixture in the same manner. Then sprinkle cheese over the top of everything.
Put the baking dish, uncovered, into the oven and cook about 25 minutes, or until it is bubbling more than just at the edges. Turn the oven up to broil and cook about 5 more minutes or until the top is looking extra bubbly and delicious, but not to the point that the cheese is dried out.
remove from the oven and let it rest at least 5 minutes before serving. Garnish with a sprinkle of paprika and some minced parsley, if you want to add some color.
