Press cheese through a fine sieve. In a large bowl, with mixer at medium speed, beat butter with sugar until fluffy. Then beat in egg yolks, cheese, sour cream, raisins and vanilla. Now carefully blend in 1/2-cup heavy cream, whipped. Line a sieve or colander with cheesecloth. Spoon in cheese mixture, then fold ends of cheesecloth over top. Set in a large bowl to catch any drippings. Refrigerate over night.