Add the egg yolks, oil and butter to a mixing bowl, and blend until well combined.
Mix in the remaining ingredients, and stir well to combine.
Chill the batter in the fridge for 1 hour until set.
Preheat the oven to 350 degrees.
Drop the batter by the spoonful onto a parchment lined baking sheet, and form into a cookie shape.
Bake for 10 minutes.
Allow to cool completely before serving.
