Wash and peel the potatoes. Keep them immersed in water to prevent them from turning brown as you work with them.Using a mandoline slicer (#3 thickness), slice the potatoes lengthwise into ⅛” slices. Keep the slices immersed in water.
Make the sauce
In a large heavy-bottomed skillet, heat 1 teaspoon of olive oil. Add ½ of one onion, sliced, and sauté on medium heat with a pinch of salt until they soften. Stir ever so often to prevent burning.Add 1 tablespoon of the Litehouse® freeze dried garlic, cauliflower florets, and paprika. Sauté until the cauliflower just begins to brown. This will bring out the flavor better.Add the vegetable stock and bring to a boil. Cover, reduce the heat to low and let the cauliflower cook until soft.Remove from heat and let cool completely uncovered.Transfer to a blender. Add nutritional yeast and lemon juice and blend until smooth.Adjust salt to taste. Set aside.
In the same skillet, heat 1 tablespoon of olive oil. Add the remaining 2 sliced onions and cook on medium-low heat with a pinch of salt until they soften and turn a light brown. Watch carefully so they don't burn.Turn off heat and let cool completely. They will continue cooking and softening in the residual heat.
Preheat oven to 400°F.Spread a thin layer of the cauliflower sauce at the bottom of the casserole dish.Arrange a single layer of potato slices, overlapping them as you go.Spread another layer of the cauliflower sauce.Top with the caramelized onions. Sprinkle chives and freeze-dried garlic.Season with salt and pepper. Then drizzle about a ½ teaspoon of olive oil.Repeat steps 3-6 until you run out of the sauce, ending with a layer of potatoes.Brush the potatoes generously with oil then top with the remaining caramelized onions.
Cover the casserole with foil.Bake in the preheated oven at 400°F for 30 minutes.Uncover, increase the temperature to 425°F and continue baking for another 30-35 minutes, or until the potatoes are cooked through and the sauce is thick.Let the casserole cool for 10 minutes on a wire rack. This will allow any extra liquid to be absorbed back into the potatoes. Serve warm.The casserole can be refrigerated for up to 3-4 days, or frozen for up to 2 months.
* If your vegetable stock is not salted (mine is), adjust salt in the sauce accordingly.