In a medium bowl cover cashews with boiling water and let soak for 1 hour. Strain cashews, place in blender with evoo, lemon juice, vinegar, water and salt.  Blend until smooth. Let it sit in fridge for at least 1 hour. 

With a box grater or food processor, grate potatoes, carrot and zucchini into a towel.  Squeeze out all liquid and place dried grated vegetables into a bowl.  

Add flour, corn starch, salt and pepper, mix well with hands.  

In a large frying pan heat oil over medium-low heat. Drop several spoonfuls of the mixture into hot oil without overcrowding the pan. Using the back of a spoon, pat down each latke to flatten it. Putting them too close together will make them soggy and difficult to flip. 

Fry 3 to 4 minutes on each side, until golden and crisp around the edges; repeat procedure until finished with all the batter.

Serve with vegan sour cream.