Preheat oven to 400 ℉. Lightly grease a small casserole dish with coconut oil.
Place thawed spinach in a clean tea towel and squeeze out excess water.
In a high power blender, combine soaked cashews, almond milk, Dijon mustard, lemon juice and zest, nutritional yeast, garlic, salt and pepper. Process smooth, about 3 minutes.
Arrange the spinach and artichoke hearts in the prepared casserole dish. Pour cashew cheese mixture on top. Use a spoon to evenly distribute artichokes and spinach throughout cashew mixture.
Sprinkle surface with remaining 1 tablespoon nutritional yeast. Cover with foil and bake 15 minutes. Remove foil and bake 5 more minutes.
Let sit 10 minutes before serving.