Add all the ingredients to food processor or blender in the order listed (minus walnuts) and blend until smooth.
Stir in walnuts, if using.
Let batter sit for 5-8 minutes.
Heat a pan or griddle over medium to medium-low heat.
Coat pan with butter or oil.
Drop 1-2 tablespoons of batter into the pan.
Cook until bubbles start to form and the edges of the pancake begin to appear solid (about 3 minutes).
Carefully flip.
Cook for another 2-3 minutes.
Serve as is or with topping of choice.
