Preheat the oven to 350°F. Line a baking sheet with parchment paper.

To make the dough: In the bowl of a stand mixer fitted with the paddle attachment, add the butter, dark brown sugar, and cane sugar. Mix on low until combined and there are no chunks of butter.

Add the eggs, flour, oats, cinnamon, baking soda, and sea salt in that order. Mix on low until a stiff dough forms. Add the raisins, and mix on low until combined.

Using your hands form a large log out of the cookie dough and flatten slightly so it’s about 1-inch thick, it should be about 13 x 3 inches.

To make the glaze: In a medium bowl, add the powdered sugar and milk. Whisk until a smooth glaze forms, drizzle over the tops of the biscotti.

Store in a cool dry place for up to 7 days.