Preheat the oven to 400°F.
Ensure the cashews have soaked in boiling water for at least 30 minutes. Drain and blend the cashews, mayonnaise, water, lemon juice, nutritional yeast, and apple cider vinegar in a high powered blender for 1-2 minutes until smooth.
Pour the mixture into a medium sized bowl. Add the remaining ingredients and stir with a spatula until combined.
Place the mixture in an oven safe dish and bake at 400°F for 20 minutes. (This quantity filled 2 french onion soup bowls.)
Carefully remove from the oven and enjoy! Best served hot with crackers, chips or vegetables. The mixture can be prepared ahead and stored in the fridge, covered, to be baked the next day. Leftovers can be stored in the fridge, covered, for 2 days.