I filled them with this Swiss chard recipe adapted from Mark Bittman:
2 pounds Swiss chard
2 tablespoons olive oil
1 tablespoon minced garlic
1/2 cup pine nuts
1/2 cup currants (preferred) or raisins (I used raisins that I chopped up a bit), soaked in warm water for 10 minutes then drained
Salt and freshly ground pepper to taste
1. Prepare the chard: Wash the leaves well in a sink full of cold water. Cut the thick stems out of the leaves. Roughly chop the stems and the leaves, separately. Steam the chopped stems over simmering water for five minutes, then add the leaves and steam for another few minutes until thoroughly wilted. The chard will shrink dramatically in volume. Remove from heat and allow to cool. Squeeze chard dry with a kitchen towel, then chop some more.
2. Place the oil and garlic in a large skillet over medium-low heat. Cook for a couple of minutes, until garlic begins to color.
3. Add the pine nuts and cook another minute, stirring, then add the chard, currants, and salt and pepper. Cook, stirring, for about two minutes, until heated through.
These would probably be good with Cheezy Sauce on top. Next time I'll try that.