I’ve had an inappropriate amount of fun covering COOK’s Open Stove series for The COOKbook in 2012. From clashes European and North American to battles between bartender bros and actual brothers, the monthly competition ranged wildly in theme and personnel, but a sense of jovialty and culinary fellowship (often in the form of dude-hugs) pervaded each installment. OS9 was no exception, bringing together two chefs from two very different kinds of bars for a competition characterized as much by goofs as good food.

Kevin Yanaga (left) mans the sushi bar at Rittenhouse’s Zama, and is well-known at COOK for his fishy stylings and expertise in knife sharpening. Mark Regan (right), too, has appeared at COOK frequently, but this Open Stove was the first opportunity for the chef de cuisine of Newbold beer bar South Philly Tap Room to lead the charge.

Yanaga, joined by sous chef Pila, and Regan, backed up by his also-a-chef roommate Scott, were informed of the always-unpredictable format from go: Each chef would be required to prepare four courses, with just two, an amuse bouche and dessert, conceived ahead of time. The apps and entrees would be dictated by secret ingredients selected by the COOK staff — past momentum-squelching surprises have included Spam, Colt 45 (fave) and Lucky Charms. Given its unpredictable nature, it’s a pursuit for good sports with good jokes — something both Yanaga and Regan possess in abundance. Having an abundance of sake within arm’s reach rarely hurts, either.

The evening-opening amuse aptly reflected the differences between 0s9’s competitors. Yanaga hit a slew of classic Japanese flavors with his picturesque starter, a Japanese “deviled egg” (left): soft-boiled, dashi-marinated, then filled with uni, soy, wasabi and salmon roe next to a stroke of ink-black nori puree. Regan represented the adventurous but accessible direction of the cooking at SPTR, frying pucks of creamy head cheese and pairing them with a simple slaw of Brussels sprouts and fennel.

Then came the first secret ingredient of the evening: organic chestnuts, not roasting on an open fire the way Nat King Cole likes ’em, but shelled and sealed in snazzy packaging. Yanaga, wielding some pretty portions of fish, sparked his trusty blowtorch to roast the skin of young yellowtail, fanned out over a pesto-esque streak of basil, ponzu and chestnuts. Wrapped around the plate a drizzle of garlic-infused chili oil, which lent some welcome heat to the subtle sashimi setup.

Regan again decided to go a heartier route with his starter course: couscous cooked in the risotto style, with generous hunks of romanesco (cauliflower from space!), chopped chestnuts, bacon, sage, Meyer lemon zest and a rich binder of sage brown butter. Two completely different takes on the secret ingredient, both very successful, both showcasing each competitor’s best strengths.

Leave it to the entrée course to muck all that up!

In addition to fielding a difficult secret ingredient — Green & Black’s dark chocolate — the Open Stovers had to deal with a second cooking curveball for their main. Considering Yanaga’s familiarity with Japanese flavors and Regan’s comfort with homier American cooking, the powers that be informed them to construct their main dishes in the style of their competitor — the polar opposite of each chef’s comfort zone. This, plus the off-sweet chocolate kicking it in a savory context, made for some very interesting plates. Yanaga’s cheekily dubbed “American-style Italian risotto” (left) featured fluffy rice, a spicy mole-type situation (it’s North American), braised fish and enokis. Regan packed the pork, slicing a beautiful grilled loin and matching it with stir-fried rice with Japanese mushrooms and a dark chocolate sauce augmented with soy and orange.

Sweet, sweet dessert brought Yanaga and Regan back to their wheelhouses. Yanaga presented ice cream made with roasted green tea and an absolutely killer half-sake, half-hot chocolate concoction good enough to melt any wintry thaw. Regan sliced up homemade lemon bar squares, each pucker-up forkful complemented by toasted ginger marshmallow and macerated blueberries.

Like the eight installments that preceded it, Numero Nueve came down to an audience vote to determine the final Open Stove winner of the 2012 calendar year. Regan took this W home in a close shave, but both talented chefs seemed to have a hell of a time. OK, maybe Regan a little more than everyone else:

All Photos: Yoni Nimrod