The type of kale you use will determine the cooking time. Red Russian and dino kale will be cook faster than curly leaf kale. Taste a leaf around the 5-minute mark for tenderness.

1 T extra-virgin olive oil
1 bunch kale, washed, stemmed, leaves coarsely chopped
1/2 c water or apple juice
2 apples, cored and sliced or chopped
2 T cider vinegar
4 t whole-grain mustard, or other mustard
2 t brown sugar, optional
salt and pepper, to taste

1. Heat oil in a large skillet or pot medium heat. Add kale and sauté for about a minute. Add water or apple juice and cook, stirring occasionally, for about 3 minutes. Stir in apples; cover and cook, stirring occasionally, until the kale is tender, 8 to 10 minutes more.

2. Meanwhile, whisk vinegar, mustard, brown sugar, if using, salt, and pepper in a small bowl. Add the mixture to the kale, increase heat to high and boil, uncovered, until most of the liquid evaporates, 3 to 4 minutes.