Preheat oven to 350F.

• Beat butter, sugar and vanilla until creamy.
• Add oil and water.
• Keep mixing on lowest speed.
• In a separate bowl whisk flour and baking powder.
• Gradually add to the butter mixture while mixing on a low speed. 
• Add ground walnuts and mix just until ingredients are incorporated.
• Spray tins with a little bit of oil and fill each tin.
• Place the tins on cookie sheets and bake 22-25 minutes.
• While still warm turn the tins upside down as it will be easier to remove the cookies from the tins.
• Once the cookies cool down, squeeze a tin just a little and the cookie should come out easily. 
• Roll cookies in powdered sugar.

This recipe yields 28-30 cookies.