Here was another approach.  It doesn't look like a miracle.  It looks like art.

I painted the eyes and mouth, with just a hint of the nose.  I actually painted them with browning sauce, but I could have done it with burnt umber and had the same effect.

Then I went into the hotel parking lot with my heat gun, and lightly toasted just the edges of the tostada, just to give it some variation in tone.  The result was, like, artistic and shit.