Crisp, delicate butter lettuce leaves have a cup shape that’s perfect for holding the sweet-and-savory ground turkey mixture and crunchy, colorful vegetables.
The key is not to weigh down the cups with too much filling so they don’t tear. Add some heat with crushed red pepper or a diced red Fresno chile. The sugar here not only balances the vinegar tang; it also helps the meat caramelize and develop wonderful crispy bits in the pan.
You could use ground pork or a tofu scramble in place of turkey. If you can’t find butter lettuce leaves, you can cut romaine leaves crosswise, removing the wide part of the rib.