Plan ahead - you need room temperature butter and eggs so take these out of the refrigerator ahead of time.
Preheat the oven to 350 degrees F/175 degrees C. Line a baking sheet with parchment paper or a silicone baking mat. In a mixing bowl, whisk the flour, baking powder, cinnamon and baking soda together. Fit your stand mixer with a paddle attachment and on medium speed, cream together butter, sugar, salt and orange zest, until smooth and creamy, about 2 minutes. Add eggs, one at a time, eating for 1 minute after each one goes in and scrape down the sides and bottom of the bowl.
Beat in the old fashioned oats and turn the mixer off. Add the dry ingredients from your mixing bowl, all at once.
Mix everything on low speed until the flour is almost incorporated. Add the granola, almonds and cranberries and mix on low only until it just comes together. Do not overmix. Turn the dough out on a clean surface, divide it into two parts, and shape into logs (about 10 to 12 inches long and about 1½ inches wide). Transfer the logs to the prepped cookie sheet leaving room between the logs.
Bake the logs for about 25 minutes, rotating the baking sheet after about 15 minutes. Take the cookie sheet out of the oven. After the first bake, the logs should be cracked and lightly browned. Let the logs cool on the cookie sheet (transfer the sheet to a cooling rack if you have one) for about 30 minutes.
Once cooled, transfer the logs to a cutting board (a wide, flat metal spatula is helpful), and using a serrated or bread knife, cut into ½-inch-thick slices.
Return the slices to the baking sheet and bake for another 15 minutes.
After 15 minutes, pull the cookie sheet out from the oven, flip the cookies and bake for 10 more minutes. At this point the cookies or “biscotti” will be golden brown and slightly firm to touch.
Transfer the biscotti to cooling racks to cool and harden up before storing in an airtight container. They’ll continue to harden as time goes by.