Make the vegan cheese and set aside (see notes for link to recipe).
In a sautee pan, cook the spinach down for a few minutes. No need to add water or oil, just heat it over medium-low and stir often. It'll cook down after about three minutes.
In a baking dish, combine all ingredients, stir well, and then bake at 350 for 25 minutes, until bubbly.
Let sit for 10 minutes, then enjoy.
Notes
My go-to cheese recipe is here. Just omit the jalapeno for this recipe. And if you're looking for the best vegan mayo brands (and a pretty convincing reason of why you should support one brand over the others) look at my vegan substitution list here.