Let’s party on!

AMERICANS have been conditioned to treat the weekend after Thanksgiving as the kickoff of the race to the mall for an orgy of shopping, but it is actually something far more meaningful: the official opening of party season. For the next six weeks, any excuse will do.

And it’s not too early to start planning the first fete. Call it the after-party.

Once the turkey frenzy has subsided, there is much to be said for getting together to eat and drink and relax with friends who couldn’t be with you on the big day, or favorite relatives who were otherwise engaged. You might even have a houseful of people hanging around who need to be fed and entertained, without going out to some head-bangingly loud restaurant where it’s impossible to talk. Entertaining at home is much more relaxed and relaxing. Thanksgiving is a day of obligation. The after-party is pure indulgence.

The food is the best part. Tradition is a tough boss on the feast day; you have to have the dishes you always have, the ones everyone expects and loves. But for the after-party, you can cook and serve whatever you want. You can take the opportunity to use up leftovers or start from scratch or, ideally, do a little of both. And while American has to be the theme on the actual holiday, you can wander all over the food map in the days after.

What the menu primarily has to be is easy, after the run-up to Thanksgiving, that marathon of planning and shopping, chopping and cleaning. Make a simple appetizer, a simpler main course and a side dish, let a guest bring the dessert and salad or anything else they might want and you’re there.

Mexican flavors are close enough to American to go with whatever anyone else shows up with but exotic enough to be interesting, which is why they are the natural theme for the menu. And relying on them makes it easier to ramp up the seasoning for the whole meal. A normal Thanksgiving puts most of its spices into the pumpkin pie, but here you can use chiles and herbs with a free hand.

If you’re cooking tomorrow, you will almost certainly have enough turkey left to dice two cups’ worth for quesadillas with cheddar cheese for eight. You will probably also have cranberry sauce sitting around looking for a second chance at life. Add cilantro, scallions and jalapenos to it and it becomes a sort of salsa, the ideal accent for the sharp cheese and mellow turkey.

Ordinarily, having no leftover cranberry sauce would be good luck, but here it is bit of a misfortune. Luckily, cooking a fresh batch takes five minutes and three ingredients. I had forgotten how good the basic recipe on the bag is -- it’s just pure fruit flavor -- and it works superbly. Or you can be brave and use raw cranberries for the salsa; coarsely chop them and combine them with the other ingredients. The tartness and the crunch are positively bracing.

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Fish is now a welcome dish

AS for the main course, fish is what many people wake up craving after Thanksgiving, once the tryptophan wears off. A side of salmon is perfect. It has the same communal appeal of a whole turkey and can be cooked just as easily: season it and then roast it. A coating of chipotle chiles, sesame seeds, scallions and cilantro can be spiked with tequila and lubricated with sesame and olive oils to seal the juicy fish under a savory crust. It cooks in about a tenth of the time of a turkey and can be served either hot or at room temperature.

The vegetable to go with it would work just as well on the Thanksgiving table. Swiss chard braised with shiitakes and poblano peppers is lively and dramatic. Spinach could be substituted for the chard, but you will need probably twice as much. And green chard is crucial unless you want Christmas colors on the plate; red chard will “dye” the mushrooms.

Aside from the fish, the shiitakes, the poblanos and the chard, most ingredients for this menu are either likely to be on hand or easily picked up at even a convenience shop. You can even serve the beer or wine bought for the turkey. And if no one is quite in the mood to sit down around the table for one more big meal, it is very doable as a buffet.

One last bonus: An after-party will give you the strength to get through the mall.

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food@latimes.com

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Turkey quesadillas

Total time: About 15 minutes

Servings: 8 as an appetizer

3/4 cup cranberry sauce

2 to 3 fresh jalapenos, seeded and coarsely chopped (about 3 tablespoons)

1/4 cup chopped cilantro

4 green onions, green part only, thinly sliced

6 tablespoons ( 3/4 stick)

unsalted butter, melted

4 (10-inch) flour tortillas

2 cups diced roast turkey

2 cups grated sharp cheddar

1. Heat the oven to 450 degrees. In a bowl, combine the cranberry sauce, two jalapenos, cilantro and green onions and mix well. Add the other jalapeno if more heat is needed.

2. Use 2 tablespoons of the butter to grease a baking sheet. Lay a tortilla on it. Spread one-half cup of the turkey over one half, then spread 3 tablespoons of the cranberry sauce over the other half. Sprinkle one-half cup of the cheese over the turkey. Fold the tortilla in half and press to seal. Brush the top with melted butter. Repeat with the remaining tortillas and filling.

3. Bake the quesadillas for 5 minutes, or until the cheese is completely melted. Cut each into 4 pieces and serve.

Each serving: 402 calories; 21 grams protein; 29 grams carbohydrates; 2 grams fiber; 22 grams fat; 13 grams saturated fat; 79 mg. cholesterol; 437 mg. sodium.

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Chipotle roasted salmon

Total time: 35 minutes including marination

Servings: 8 to 10

2 chipotle chiles in adobo sauce

1/4 cup sesame seeds

1/2 cup tequila

3 tablespoons olive oil

3 tablespoons sesame oil

2 large cloves garlic, minced

4 scallions, green part only, thinly sliced

1/2 cup chopped cilantro

1 teaspoon dried Mexican oregano, crumbled

1 fillet of wild salmon, 3 to 3 1/2 pounds, about 1 1/4 -inch thick

1 1/2 teaspoons sea salt or kosher salt

1. Mince the chipotles and combine with the sesame seeds, tequila, olive oil, sesame oil, garlic, scallions, cilantro and oregano. Mix well.

2. Season the salmon with the salt. Lay the fish skin side down on a foil-lined rimmed baking sheet. Spoon the chipotle mixture evenly over the top. Let stand 15 minutes. Meanwhile, heat the oven to 500 degrees.

3. Roast the salmon for 12 to 15 minutes, depending on the thickness of the fish, or until a thin sharp knife slides in easily when inserted into the thickest part. Let stand 5 minutes before cutting into slices. Lift the foil onto a serving platter and slide the fish onto the platter. Serve hot or at room temperature.

Each of 10 servings: 298 calories; 30 grams protein; 2 grams carbohydrates; 1 gram fiber; 15 grams fat; 3 grams saturated fat; 69 mg. cholesterol; 318 mg. sodium.

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Swiss chard and shiitakes with poblanos

Total time: About 50 minutes

Servings: 8 to 10

3 poblano or pasilla chiles

3 pounds green Swiss chard

1 pound shiitake mushrooms, stemmed and wiped clean

3 tablespoons extra virgin olive oil

4 large cloves garlic, minced

1 tablespoon tamari or soy sauce

1 cup chicken stock

1. Roast the chiles over a gas flame or under the broiler until the skins are evenly charred on all sides. Let cool, then slip off the skins and stems and scrape out the seeds. Cut the flesh into a fine dice and set aside.

2. Remove the stems from the Swiss chard leaves, reserving them for another use. Wash the leaves in two or three changes of cold water. Cut the leaves crosswise into thin strips and set aside.

3. Cut the shiitakes in half

and then crosswise into thin strips.

4. In a very large skillet (or use two skillets), heat the oil over medium heat. Add the garlic and saute, stirring constantly, until just softened, 3 to 4 minutes. Add the shiitakes and cook, stirring often, for 10 minutes. Start adding the chard, a handful at a time, stirring and cooking until the leaves soften enough to allow more leaves into the pan. Continue until all the chard is in the pan.

5. Raise the heat to medium-high and stir in the tamari or soy sauce. Add the poblanos and mix well. Add the stock and cook, stirring, until all the ingredients are well mixed. Continue cooking, stirring occasionally, until the chard is completely tender, about 15 minutes.

Each serving: 92 calories; 4 grams protein; 9 grams carbohydrates; 3 grams fiber; 5 grams fat; 1 gram saturated fat; 0 cholesterol; 377 mg. sodium.