Infuse lettuce with tangy flavors by resting the chopped leaves in a sweet and sour pickling solution. This dish is enjoyed in a handful of European and Asian regions. Lettuce is not pickled as a means of preservation, as the high heat needed to prevent spoilage would turn the vegetable slimy. Cabbage and sturdy greens like kale or mustard can stand up to the heat required for shelf stability. Most palates enjoy lettuce varieties like red leaf, Romaine and iceberg when they are crispy to a bit wilted, which is achieved with refrigerator pickling. The zing of pickled lettuce makes for a delightful snack, side dish or addition to sandwiches and salads.
Combine the water, vinegar, salt or soy sauce, sugar or honey and desired flavorings to a saucepan. Taste the mixture. Adjust the seasonings, if needed. Bring the mixture to a boil over medium-high heat, stirring to dissolve the sugar.
Remove the saucepan from the stove. Let the mixture cool to room temperature.
Wash the lettuce thoroughly under cold water. Pat dry with paper towels to ensure maximum absorption of the pickling liquid for the most flavor.
Remove the lettuce leaves from the head. Lay the leaves in a manageable stack on a cutting board, working in batches if needed. Roll them up somewhat tightly from the short end, so that the lettuce leaves resemble a large cigar. Hold the roll horizontally and slice crosswise into about 1/4-inch strips.
Pack the lettuce tightly into a large glass jar, without jamming it in, allowing for about an inch of head space to the top of the jar. Pour the pickling liquid over the lettuce, submerging it completely. Leave at least 1/2 inch of head space.
Screw the lid tightly on the jar. Shake the jar gently a few times to distribute the liquid.
Place the jar of lettuce in the refrigerator. Allow the lettuce to rest for a half hour or longer before consuming. Use the pickled lettuce within a week. Remember that the flavors build as time goes by, but the texture of the lettuce becomes softer.