I use half Bob's Red Mill(R) and another rice-based flour mix. Bob's Red Mill(R) is a bean-based flour and I like the texture it gives the biscotti. If your flour mix already has xanthan gum added, you can omit. It needs to have a total of 2 teaspoons xanthan gum per 3 cups of flour. I add 1 teaspoon because my rice mix contains xanthan gum, but the Bob's Red Mill(R) doesn't.
Vanilla extract or almond extract can be used in place of the anise seed, if desired.