Preheat oven to 350 degrees F.
Mix together flax seed and water and set aside. [Skip if using aquafaba]
In a stand mixer, mix together vegan butter, together with sugar until creamy.
Next add flax egg or aquafaba and vanilla and mix until combined.
In a separate bowl, add all dry ingredients, nuts, and raisins/cranberries and whisk.
Slowly incorporate dry ingredients into stand mixer bowl until a rough dough forms.
Remove from bowl and place on floured surface. Shape dough into a large ball and divide in half.
On a large baking sheet lined with parchment paper, shape the two balls into two large logs, approximately 12 inches long and 2inches wide. Make sure to put 3-4 inches of space between the two logs, as they will spread a bit in the oven.
Place in oven for ~25 minutes. Remove from oven and let the logs cool completely. Then, taking a bread (serrated) knife, cut the logs into 1/2 inch thick slices (I like my biscotti small!).
Place the slices cut-side down onto a baking sheet lined with parchment paper. Reduce heat in oven to 275 degrees F and bake for an additional 25 minutes. Remove from oven and enjoy.