-
1
Rip off two sheets of aluminum foil -- each about 18 inches square -- and stack them on top of each other.
-
2
Using 1 tablespoon of the olive oil, grease a patch in the center of the foil big enough to hold the two chicken breasts.
-
3
Make a bed of the cabbage and celery leaves on top of the oil.
-
4
Spread the mustard evenly on one side of each of the chicken breasts and then place the mustard side down on top of the cabbage and celery leaves.
-
5
Salt and pepper the chicken, then drizzle the sherry vinegar, honey and broth over the top.
-
6
Fold the foil over the chicken onto itself and crimp the edges as tightly as possible. Seal the package very tightly but leave plenty of room around the chicken.
-
7
Place a skillet large enough to hold the package over high heat. A minute later, add the remaining oil and pour out all but a film. Put the package in the skillet; it will sizzle. About two minutes later, the package will expand like a balloon; be careful of escaping steam. Cook for 5 minutes longer from that point.
-
8
Remove the package from the heat, again being careful of the steam. Slice it open down the middle with a sharp knife and spoon out the greens and chicken onto plate, pouring the sauce on top.
