For those of us who cannot get ramps, what's the best substitute in this recipe, and how much of that ingredient should we use?

I agree wholeheartedly with louisez--garlic chives have a flavor that most closely approximates those of ramps. Green garlic isn't a bad substitute either.

Possibly garlic chives?

A question about this was asked about a year ago
http://food52.com/hotline/14568-a-question-about-a-recipe-ramp-car

I was under the impression that they don't grow around here because they need a cold winter. I've never seen them. I suppose it's possible that they grow up near the Sierras. The idea to check the Berkeley markets is a good one, though. Berkeley Bowl might have them, too, if anyone does. Or perhaps someone at the market at the ferry in SF. Thanks! ;o)

I wonder if using Spring onions would be a good substitute. The ones that pop up in my vegetable garden are just tiny wisps when they are newly growing, before they become onions. Have you tried chasing down ramps in the great markets of Berkeley ? (let me know)