Preheat your oven to 350 degrees
Use an electric hand mixer to cream 8 tablespoons of room temperature butter with 2/3 cup of granulated sugar in a large bowl
Add 2 large eggs, 2 tablespoons of fresh orange juice, 1 tablespoon of fresh orange zest and a teaspoon of vanilla extract and mix on medium speed until light and fluffy
Sift 2 cups of all purpose flour, 1 1/2 teaspoons of baking powder and 1/4 teaspoon of salt into the bowl and use a silicone spatula to mix until the ingredients are just combined
Gently fold 3/4 cup of chopped pistachios and 3/4 cup of chopped white chocolate into the dough until evenly distributed
Transfer the dough onto a parchment paper lined baking sheet and use lightly dampened hands to form the dough into a large rectangle that is about an inch thick evenly throughout (see photos above)
Bake the dough in a 350 degree oven for about 25 minutes or until the dough is puffed, feels dry and lightly set throughout
Transfer the baking sheet onto a heat proof surface and use the parchment paper to carefully slide the dough onto a cutting board (leave the oven at 350 degrees)
Use a sharp knife or serrated knife to cut the dough into even 1 inch thick slices and then cut each slice in half (see photos above)
Transfer the portions onto a baking sheet on one side and return the cookies to a 350 degree oven
Bake the biscotti for about 10 minutes per side (20 minutes total) and then transfer onto a cooling rack to cool
To garnish, whisk 1 cup of sifted confectioners sugar with about a tablespoon of freshly squeezed orange juice to form a drizzle-able consistency. Dip the tops of each cooled biscotti into the orange glaze and sprinkle with finely chopped pistachios and white chocolate. Return the garnished biscotti onto the cooling rack to allow the glaze some time to set
Enjoy with coffee or tea
Store biscotti in an airtight container at room temperature