Mix the cardamom into the yogurt and refrigerate until you are ready to serve.
Toss the peaches with the lemon juice so they won't oxidize. Put the Zinfandel and sugar into a stainless steel pot over medium heat and bring it to a simmer. Add the peaches and simmer for about 15 minutes, covered. Remove the peaches and reduce the Zinfandel by about half, down to light syrup. Spoon the sauce over the peaches and serve with the yogurt.