Place the cashews in a bowl and cover with water. Let sit for 30 minutes.

Heat the oven to 450 degrees.

Slice the sweet potato into rounds. Toss with a tablespoon of olive oil, salt and pepper. Place on a baking sheet, and bake for 30 minutes, turning once half way through.

Slice the onion, shallot, zucchini and garlic. Cook for 5 minutes in a large skillet over medium heat (add oil if you want, but with the juices in the veggies, I don't think you'll need it). Next, add the spinach, and cook a final 5 minutes, until the veggies are tender and the spinach has wilted.

Make the cashew sauce: drain the cashews, and place in a high powered blender. Add the white onion, garlic, water, nutritional yeast, avocado and sriracha. Blend on high for a minute or two, until all ingredients are combined.

Heat your panini press, and drizzle olive oil on the outsides of your bread slices. Make your sandwiches with the sweet potatoes, the onion mixture, and a few spoonfuls of the cashew cheese sauce, and heat on your press for 5 minutes.