Vichyssoise recipe needed

My grandmother (pre-alzheimer's) used to make this for me everytime i would visit and it became my favorite childhood dish. I was really young and used to help her make it but i cant remember what all she put in it. I know its pretty much Potatos, Half & Half, Chicken Broth, and pretty much salt, pepper, garlic powder. I just cant make it like she could. I think im lacking on technique more than anything else but its just not the same. I cant get it as smooth as she could..mine kinda has a gritty txture... if anyone has a recipe they use or any sugestions, it'd be appreciated. Thanks in advance.