milk and egg yolk instead of butter?

[nappyaddict]

I remember using 100ml of milk and 2 egg yolks in a flapjack recipe once instead of butter. I was just wondering if this would work in chocolate brownies as well?

Hmmm, I'm no food scientist, but I would have thought that butter would be fairly critical in a brownie (being as it's usually fairly equal ratios of butter, eggs and chocolate) - this would skew the balance quite significantly?

Apparently apple, prune or sweet potato puree works in place of butter too.