Preheat oven to 300 degrees. Line two baking sheets with parchment paper or silicone baking mats.
Put the flour, salt and baking powder in the bowl of an electric mixer fitted with the whisk attachment. Mix on low to combine. Add the eggs, olive oil, agave, vanilla, lemon zest and juice. Start the mixer on low then turn it up to medium and mix the ingredients, scraping down the sides of the bowl once. Stir in the pistachios and cranberries. Divide the dough evenly putting half on each of the prepared baking sheets and, with wet hands, shape into logs or ovals about 9 by 3 inches. Bake for 30 minutes or until the dough feels firm to the touch and is lightly browned. Remove from oven, increase the temperature to 350 degrees and cover each log with a doubled over tea towel. Let sit for 10 minutes.
Remove the logs from the baking sheets to a cutting board and using a thin, sharp knife or serrated knife, cut the biscotti into ½ inch pieces on the diagonal. Place the biscotti back on the baking sheets and bake for 10 minutes or until golden browned.
Store in an airtight container - especially important if you are in a humid climate.
*You can make your own gluten-free flour blend by whisking together 1 ½ cups superfine white or brown rice flour: ¾ cup tapioca starch, ¼ superfine sweet rice flour and 2 teaspoons xanthan gum