First, make the orange cookie dough. Add the vegan butter, sugar, and orange zest to a large bowl and cream together until light & fluffy (about 1 minute). Then, add in the orange juice and ground flax seed and cream together another 30 seconds. Add in the flour and mix until a thick cookie dough forms. The cookie dough will be relatively thick, but it should not be crumbly so keep mixing until it holds together.
Add the cookie dough to a sheet of parchment paper. Then, layer another sheet of parchment paper on top of the dough. Use a rolling pin to roll the cookie dough between the two sheets of parchment paper into a rectangle about ½ inch thick in height.
Once the dough is rolled out, make the cranberry filling by adding the frozen cranberries, sugar, and orange zest to a blender or food processor. Blend until the cranberries have been finely chopped and are evenly mixed with the sugar.
Remove the top layer of parchment paper from the cookie dough and add the cranberry filling on top. It is very important to add the filling while it is still cold for the best results.
Then, carefully roll the dough into a log. Press the dough edges together to seal. If the dough cracks at all while you roll it up, lightly press it back together and continue rolling. Also, make sure not to let the filling ooze out of the sides of the dough as you roll it up.
Next, lay parchment paper on top of a large baking tray and place the rolled up cookie log on top. Place the tray with the log in the freezer for at least 15 minutes to solidify before cutting.
While the dough is in the freezer, preheat the oven to 350F. Then, remove the dough from the fridge, place it on a cutting board, and slice into 16 cookie slices that are about 1 inch thick.
Lay the cookie slices onto the baking tray covered in parchment paper, making sure to leave space between each cookie. Bake for 14-17 minutes or until firm and very lightly browned (too browned will mean you overcooked them and cooking time will vary on how thick you cut the cookie slices). Remove from the oven and let cool on the baking sheet for at least 15 minutes. Then, remove and place onto a wire rack to finish cooling.
Once the cookies have cooled make the (optional) glaze. Add the orange juice and sifted powdered sugar to a small bowl and whisk together until a thick glaze forms. Then, drizzle the glaze over the cookies. Let the glaze harden for 1-2 minutes, then serve!
Notes:
Cookies can be stored in a closed container at room temperature for 3-4 days, in the fridge up to 1 week, or in the freezer up to 1 month.