Heat oven to 375 degrees F. Coat sides of 9-inch tart pan with removable bottom with nonstick cooking spray. Drain peaches and thinly slice; reserve syrup.
In bowl, combine biscuit mix, 1/3 cup cinnamon sugar, 1 container yogurt and oil; stir until blended. Evenly spread into tart pan. Arrange peach slices in circles on top. Sprinkle with remaining 1 tablespoon cinnamon sugar.
Bake at 375 degrees F until golden and toothpick comes out clean, 35 minutes.
Meanwhile, place peach syrup in small saucepan. Boil until thickened, about 5 minutes. Remove from heat.
Let kuchen cool in pan 10 minutes. Remove side of tart pan; place kuchen on serving plate. Brush with peach syrup. Serve with dollop of additional yogurt on side. Makes 8 servings.