Okay. Cut up 3 1/2 cups butter into 1 tblsp chunks (don't have to be exactly 1 tblsp chunks). I used 1 cup of whites, 2 cups of sugar combined in the mixer bowl and stirring constantly while the bowl rested over a pot of water, cooked to approximately 160 (over 150, not quite to 160). Removed from heat and beaten on 8 on the KA until stiff. Then, added 2 tablespoons vanilla...beat until well combined while scraping bowl. One chunk at a time, added 1/2 the butter. Then, just pulling off chunks at a time, added all of an 8 ounce block of cream cheese...scraped bowl periodically...followed by the remaining butter chunks, again, one at a time. Beat long time more...like a few more minutes.
I used the wire beater through the entire process.
If it goes sloppy on you, chill it for a bit then continue beating.
If I were to make it again, I may consider adding a bit more sugar.
It's rich, creamy, and incredibly delicious! I forgot to take the layers out...so they're thawing now. I will post images after I get them iced and decorated.