Like at a lot of households this time of year, mornings before school at the Littlefields’ start with sandwiches. They might be turkey with mayo and lettuce, or classic PB&J. They’re all on the menu now that school’s back in session. Making them can become so routine it feels like sleepwalking. That doesn’t mean, though, that the same old sandwich has to taste boring.

With a few simple additions, the standard kid’s lunch-sack sandwich can be transformed into something tastier for grown-ups. Think of it as going from “day” to “night,” like those fashion-magazine suggestions for outfits.

To get some ideas, we headed to UnChu Littlefield’s home in the Arden, Calif., area. She writes the blog “Tate’s Kitchen” (TatesKitchen.com), and tests recipes for Cook’s Illustrated. She’s also especially swift with making sandwiches for lunch, being the mother to an adorable second-grader named Ada.

As with many elementary school-age kids, Ada’s sandwich tastes are simple and more than a little fussy. The bread has to be Home Pride Split Top Wheat. And there can’t be any tomato in her “BLT.”

“She calls it a ‘BL,’ ” Littlefield said as her daughter eyed a plate of freshly cooked bacon. “She’s a picky, picky eater. She always knows when I try to cheat.”

Mom’s taste buds are more adventurous. She keeps her fridge stocked with an assortment of spreads and produce.

Littlefield demonstrates by making a quick sandwich for Ada: turkey on wheat with mayonnaise and lettuce. Then, Littlefield makes one of her own. The turkey stays the same, but out goes the iceberg lettuce in exchange for baby spinach and alfalfa sprouts. Instead of mayo, brie cheese and homemade apricot jam.

For the Littlefield family, the marinated Korean beef known as bulgogi is a great equalizer for lunch or dinner. Some slices in wheat bread makes an easy sandwich for Ada. Substitute a steak roll slathered with blue-cheese dressing, top it with homemade slaw, and the sandwich starts getting into food-truck territory.

The trick is keeping these sandwiches fresh until lunchtime. One of the more high-maintenance methods is to keep most of the sandwich ingredients in separate containers and assemble them right before eating.

If you don’t mind taking a few extra steps to splice a sandwich together, Tanya Steel, editor in chief of Epicurious.com, recommends investing in a few inexpensive bento boxes.

“Anything that’s wet can be put in its own special section,” Steel said. “That’s very useful, especially for tuna. You can include a plastic knife and then put it on the bread.”

Steel also suggests packing sandwiches with an extra helping of dark leafy greens next to the bread. Throw away any soggy greens come lunchtime and you should still be left with enough leafiness for the sandwich.

Littlefield sometimes uses a little spread of butter on the bread to maintain the sandwich’s structure. The butter helps to keep any juices from soaking the bread. An extra-sturdy style of bread or roll also will help the cause.

No matter what, thinking ahead and not saving all sandwich prep work for the morning is a good idea. Steel opts to prepare dinner and fixings for the next day’s lunch all at once.

“That’s a time saver,” she said. “The last thing I have time for (in the morning) is to make lunch. I’m too busy yelling to wake them up.”