ISO - Black Bottom Muffins

A client of mine is craving "black bottom" muffins she had once while visiting Haight and Ashbury at a coffee shop/cafe/bakery that has seemed to escaped her memory. If any of my SF Hounds can point me to a place that can provide such a treat (and even better yet, provide delivery!) I would appreciate it.

For those uninformed (me included), she described a "black bottom" muffin as a chocolate and vanilla type muffin all mixed together....I couldn't understand the full description as she started to drool and go into nostalgic convulsions.

ayudame por favor