If you're lucky this holiday season, you'll have lots of delicious leftovers. If you're creative, you can throw together a medianoche or Cuban Sandwich. And it's appropriate for New Year's Eve, because medianoche means "midnight", and a salty savory sandwich like this would go very well with a young bubbly wine full of crisp acidity.
Take a soft, long loaf of bread and slice it open lengthwise. If it's really tall, you might want to slice an inch out of the center. On the bottom slice of the loaf, lay down some mustard. The traditional option is just yellow mustard, but I prefer Dijon, and I also add a bit of mayo, which I know is anathema to some purists. Whatever your spread, layer on sliced Kosher dill pickles. Again, opinions vary: delis and restaurants tend to skimp here, but I say double up on the pickles. So much of the flavor comes from pork that you need something tart and acidic to balance it out. Then layer the sliced pork loin (or shredded pork shoulder, or whatever roasted pig you have on hand), the ham, the Swiss cheese, and finally the top half of the loaf.
Many guides will tell you to butter the inside of the bread, and I will admit that this is tasty. But I prefer to spread the butter on the outside, as it aids in crisping. With a manageable 12" loaf, I'll do it in a skillet and press it down with a casserole dish, but with anything longer you'll want to do this in the oven, on a cookie sheet, with another sheet on top of the sandwich and a set of weights on top of that to press it all together (clean bricks are ideal). Flip it occasionally to make sure both the top and bottom get equal heating.
Personally I prefer the shorter sandwich in the skillet or on the griddle; like I said, take anything solid and sanitary and press down as hard as you can on top of the sandwich while it's grilling. Not only will it smash the flavors together but the bread will become this buttery, crusty, compressed wonder. (If you're using a fancy panini press, just heat up the meats beforehand, otherwise you'll have a hot exterior and a cold interior.)
Traditionally this would be served with French fries or perhaps rice and black beans. Both are delicious, but in the interest of balance and digestion, I'd heavily recommend a salad with a light vinaigrette or some fresh fruit. As wholly delicious as this sandwich is, keep in mind that it's a concentrated mass of meat, salt, fat, and starch. The pickles and mustard are key to balancing it out, but they're not quite enough. Make a salad, grab some celery sticks, or even go with cole slaw. It's all about harmony, folks.