"Blondies"

I've baked a few batches of these recently, and was waiting until I got them right before posting about them... but I don't think I'm going to, really, so here you go anyway. It's an American recipe for "Blondies" (a non-chocolate alternative to "brownies", both of which we in Australia would normally just call a "slice"). I found it here at Cookie Madness.

They look really good, and they have a great texture and taste, but I just can't get rid of this weird aftertaste in my mouth. Not so much an aftertaste, even, more a weird feeling, like strange invisible dry bits are stuck around my mouth. I don't know what it is - maybe I'm not browning the butter correctly, or not taking it out of the oven at the right moment... I don't know.

If anyone has any ideas, I'm all ears... I really like these, apart from the weird mouth feeling!