Soak the cashews in enough water to cover and set aside. Preheat the oven to 325.
Peel and chop the turnips. Put them in a steamer and cook for 15 minutes or until they are soft enough to mash up.
Finely chop up the mushrooms (you can throw them in a blender for a few seconds, just don't puree them). Add them to a large pan with the veggie stock paprika, salt and pepper and let simmer on medium for about 10 minutes. Turn the heat down to low, add the lentils and cook for another 20 minutes. Add the peas for the last 3-4 minutes. Most of the liquid should be cook off and the mushrooms should have shrunk down quite a bit.
Mix the cashews and 1 1/2 cups of water in a food processor until it forms a cream.
Mash the turnips in a bowl. Add 1/4 cup of the cashew cream mixture, the nutritional yeast, garlic, salt and pepper and mix well. Set aside.
Add the rest of the cashew cream to a pot on low with the other cup of water, the agar agar, nutritional yeast, salt and pepper. Cook for at least 15 minutes, stirring frequently. This should start to thicken up quite a bit, but still be creamy.
When everything is cooked, start layering your pie in a casserole dish or bowl with a flat bottom. You will be making 2 layers of each item. Start with half of the turnips, then add the mushrooms/peas, then the cheese sauce, and repeat.
Place in the oven and cook for 15 minutes (at 325).