How to Make Homemade Starbucks Frappuccinos. Karen Pohl's recipe for a Mocha Peppermint Frap. To blender, add: 6 ozs milk (any milk or milk/whipping cream combo), 6 ozs espresso, 2 T real maple syrup, 2 T dark chocolate syrup, 1/8-1/4 tsp xanthan gum (to thicken it...this is in the Starbucks frap base), drop of peppermint extract, crushed ice. Makes 2 grande size fraps. Note: I make my espresso with a French press. See my pin.