Start by adding the old-fashioned oats and dry roasted cashews to a blender or food processor. Blend until they reach a fine flour consistency.
In a mixing bowl, combine the oat-cashew flour with baking powder, salt, cornstarch (or arrowroot powder), ground cinnamon, and nutmeg if you’re using it. Mix well.
In another bowl, whisk together the melted coconut oil, milk, eggs, maple syrup, and vanilla extract until smooth.
Pour the wet ingredients into the bowl with the dry ingredients. Gently mix until just combined.
While you’re mixing, preheat your waffle iron according to the manufacturer’s instructions.
Once the waffle iron is hot, lightly grease it and pour an appropriate amount of batter onto the center of the iron. Close the lid and cook according to your waffle iron’s instructions, about 4-6 minutes.
Remove the waffles carefully and serve warm with your favorite toppings.