Mashed lima bean "potatoes":
Prepare the garlic for roasting by removing all loose papery skin and slicing off the top of the bulb to expose the top of the cloves. Drizzle with some olive oil to cover the bulb and soak the exposed tops.
Wrap in aluminum foil and bake in a preheated 400-degree oven for 45 minutes or until the cloves are butter-soft. You can test this by piercing the garlic bulb with a fork.
Once the garlic is cool enough to handle, squeeze out the cloves.
Soak the lima beans in plenty of water for one hour. They will expand quite a bit, so make sure you use a large container.
Drain out any remaining water and place the lima beans in a large pot with three inches of water to cover.
Bring the water to a boil, cover, and let the beans cook 30 minutes or until they are really soft and squish easily when pressed between two fingers.
Drain out all the water using a colander.
Place the beans in a food processor with the roasted garlic, rosemary or sage, ground black pepper and salt, and olive oil and, in batches if necessary, process until you have a smooth puree.
You can check the salt and eat the "potatoes" as they are at this point, or you can whip them to improve their texture even more.
To do this, place the lima bean "potatoes" in a stand mixer with the lemon zest and, using the whisk attachment, whisk for two minutes over medium-low speed until the bean "potatoes" are airy and light. Check for salt before serving.
Soak the cashews in water to cover for half an hour.
Drain the cashews and then blend with 1 1/2 cups of water until you have a very smooth milk. You can skip this step by using store-bought cashew milk.
Heat 1 tsp of oil and add the flour to it. Cook, stirring continuously, until the flour begins to turn a light brown.
Add the onion powder, stir, and then whisk in the cashew milk, stirring constantly with the whisk to break up any lumps of flour.
Add the herbs, tamari and ground black pepper to taste. Add more salt if needed. Add the fried onions.
Let the gravy thicken, which it should do within a couple of minutes.
Pour over the mashed lima bean "potatoes" and serve.