As you may remember, several weeks ago I posted a whole wheat goat-cheese and peach pizza, proof that I'd acclimatized to Northern California.

Lauren spotted this innovation and struck back, challenging me to a Cali-cuisine duel and throwing down the gauntlet with a salad. It was a nice attempt, with backyard greens and spearmint, plus grapes, apples and dill havarti. But was it California? Sure, there were home-grown Napa grapes, but the DOP chestnut honey was the tip: Lauren's heart still lingers in Italy.

Her salad looks tasty, but it doesn't really answer the ultimate question: What Would Alice Waters Do?

Oyster mushroom ceviche, that's what. It's local, it's fusion (Bay Area hippie-veggie with Central Valley migrant-Mexican), it's completely bonkers, and it's delicious.

• 1/4 lb. each of Solano Mushroom Farm's oyster and miyazaki 'shrooms, brushed and trimmed.
• Juice of ~ 4 Yolo County limes, or enough to completely cover the mushrooms.
• Kosher salt to taste

Mix these guys together while you work on the other ingredients.

• One quarter torpedo onion, sliced thin. These are huge mutant red things, but you can use a little bit of regular red onion, too.
• One serrano chile, sliced thin. Or whatever you want, I'm not your boss.
• A couple sprigs chopped flat-leaf parsely from the backyard.

Extreme Mushroom Closeup

The dish tasted best having marinated for an hour or more—the mushrooms will become tender and the onion will mellow out. Serve it with a little Mexican crema to cool it down, commando-style or on crackers. (Could've used creme fraiche, too.)

So there it is, Lauren. I'm looking forward to the potluck.