Preheat oven to 350°. Spray a baking sheet with cooking spray, set aside.
In a medium mixing bowl, combine the flour, xanthan gum, baking soda, salt, onion powder and Parmesan cheese. Add the butter and honey and mix until the dough resembles coarse crumbs. Stir in toasted sesame seeds. Add the milk and vinegar. Shape dough into soft ball. (Or, place all ingredients in food processor and blend until mixture forms ball.) Shape the dough into 20 balls, each 1” diameter and place on baking sheet at least 2” apart. Using the bottom of a drinking glass or a rolling pin, flatten the balls to approximately 1/8” thick. Use your fingers to smooth circle edges. Bake 12-15 minutes, or until crackers look firm and slightly toasted. Turn each cracker over and bake another 5-7 minutes or until golden brown. Yield: 20 crackers