Bulletproof coffee

I've done my own version in the past. I also added egg yolks from local eggs. The egg yolk was fantastic, it helped the fats stay emulsified. I also added heavy cream. Long time go though don't remember the specifics.

Anyone add cheese? I hear that's the going trend/gross thing to do with coffee... Like a chunk of cheddar or colby jack. Purely hearsay, I've never tried it, but I hear it's one of those trendy things to do with coffee.