Add vanilla, butter and sugar to a bowl! Blend with hand mixer until creamy. Add ground walnuts and flour and mix. Scoop 1 tbsp of dough and roll into a ball. Put in the oven at 350 degrees F for 12 minutes! They should be golden brown on the top. Don’t be afraid to let them go another 5-10 min! Roll in powdered sugar and return to tray for further cooling.