Preheat the oven to 350°F; line a standard-sized (17x11-inches) baking sheet with parchment; set aside.
Remove from the oven. Lift the baked dough up, holding onto the paper and transfer to a wire rack to cool to cool on the paper for 15 minutes.
Remove the baking sheet from the oven and turn the biscotti over. Reduce the oven to 300°F. Bake for another 8 - 10 minutes. Watch the cookies carefully during this baking cycle. Do not allow them to burn or over-brown.
If you use large brown sugar with large crystals such as turbinado, add the milk and vanilla in with the sugar and butter. It takes a lot of water/liquid to dissolve coarsely ground sugar. The little water in the butter or margarine isn't enough.
To Make Traditional Hermits:
Make the dough as instructed, but omit the 2 teaspoons of milk and reduce the egg to 1/2 beaten egg.
Then, bake in a 375°F preheated oven for 10 - 15 minutes or until brown or cooked around the bottom edges.
https://glutenfreerecipebox.com/gluten-free-hermit-biscotti/