The onion-pear sauce for this pot-roasted pork has its origins in an imprecise recollection that has been rattling around in my memory since some time in the late 1990s or very early 2000s. My wife, Jackie, and I were in London, at Pierre Koffmann's three-Michelin-star restaurant La Tante Claire, then in The Berkeley hotel (where the chef now operates the excellent Koffmann's). That I know for sure, but then the memory becomes vaguer: I recall no specifics, but some dish or other incorporated a perfectly balanced oniony sauce or compote that was round in flavor, sweet and slightly acidic. When I asked him about it, Mr. Koffmann said that he'd cooked lots of sliced onions, added a bottle of decent Sauternes, gently reduced it to a syrup, then added another bottle of Sauternes and repeated the reduction. Not such useful information for those of us whose stocks of Sauternes are limited or non-existent, but a great technique and a salutary reminder for people who wonder why eating in fancy restaurants - good ones - is rarely inexpensive.
Then, a couple of months ago we were given a bottle of pink sparkling wine (could it have been a Crémant de Bourgogne?) that we opened one evening thinking it would be dry, like a brut rosé Champagne. But it was very, very sweet - not what we wanted to drink that night - so I returned it to the fridge and opened a bottle of something else. It sat there losing effervescence and appeal until several days later, when I thought of Mr. Koffmann's onions: I peeled, halved and sliced a couple of medium onions, sweated them for a few minutes in butter, nicely salted, and added half the sweet wine. Over medium-low heat, I reduced it to nearly nothing, then added the other half-bottle and reduced to a lightly syrupy consistency: still liquid but with a bit of viscosity.
Well, the resultant 2/3 cup of onion sauce base tasted flat and kind of unpleasant: yes, it had oniony sweetness, but it was also acidic in a thin, one-dimensional way, with none of the honeyed richness that Sauternes and Pierre Koffmann's skill would have generated. Still, I felt it could be salvaged, so I stowed it in the freezer.
I defrosted it last week when we brought home a little two-person boneless pork sirloin roast urged upon us by one of New York's more interesting butchers, Adam Tiberio, who deals only with local farmers who pasture-raise their animals without drugs or hormones and who has a lot of imagination when it comes to recommending unexpected cuts of meat. (Chuck "short rib" as a steak? Deliciously beefy.)
When reheated, the onion-wine base was as I remembered it: sour and boring, though with a good foundation of onion. To round it, I added about half a cup of chicken stock (other stock would have been fine) and simmered it for a few minutes to concentrate the flavor of the stock. This was partly successful, especially once I'd added salt, and I knew that the pork juices would eventually help a lot. But it was still not going to be really delicious without further intervention.
This took the form of a quickly-made chutney-like glazed pear: one firm pear, diced, cooked in a small pan with a half teaspoon of sugar, some salt and pepper and a few shreds of dried chipotle pepper (other chilies would work, of course, but the smoky chipotle remains a favorite). When the pear juices started to flow, they formed a light caramel with the sugar and the fruit took on a nice gilded color. I added a generous teaspoon of the best cider vinegar I know and simmered briefly, keeping the pears reasonably crisp though detectably cooked. This would have been very good as a condiment - and if the sauce hadn't needed its fruity sweet-sourness I'd have served it on the side.
Now, to the meat. In a small, heavy enameled iron saucepan with a good lid, I pot-roasted the pork, a fine treatment for a small but chunky cut. By this I don't mean what my mother meant when she made a pot roast: hers was a braise, with plenty of liquid. What I did was to use the heavy pan as a miniature stove-top oven: I generously salted and peppered the meat and browned it over medium-low heat on all sides, using less than a tablespoon of butter. This took five minutes. And no, the butter did not burn, though it probably would have if I'd used blazingly high heat. I added a sprig of fresh thyme, more out of habit than because it would palpably change the outcome, covered the pan and dropped the heat to low. Every now and then, though not incessantly, I removed the lid and basted the meat, which gave me an opportunity to check on its progress, inhale the aromas and verify that some nice juices were mixing with the butter in the pan - a lovely sight. Over its 25 or 30 minutes of cooking, I turned the roast two or three times.
When the roast's core temperature reached something north of 130 degrees F, I removed it to a plate and let it rest while I made the sauce. Believe me when I tell you that even a tiny thing like this needs a good quarter hour's rest before carving: it will be juicy and a little pink.
While the meat rested, I finished the sauce. I sometimes discard some of the fat from a cooking pan (never all of it, though), but tasting the mixture of butter, melted pork fat and meat juices I realized that it was too good to toss. I added the onion-stock mixture, tasted (yes, the pan juices had done their work), then stirred in the pear mixture and tasted again. Well, blow me down, I thought: this is just delicious. The sharp-edged acidity of that bottle of pink wine had been subsumed into a perfectly balanced ensemble of onion-pear sweetness and cider-vinegar tartness, with just a spark of heat from the chipotle.
And it was a perfect sauce for the pork, as it would be for any grilled or roasted pork dish. I can just about imagine a similar sauce for poultry, with the chicken (or duck) juices taking over its flavors.
Now I need to find out what that original restaurant dish was. Next time we're in London I'll ask Mr. Koffmann; perhaps his memory is better than mine.