Preheat oven to 350f. Line a baking sheet with parchment paper and set aside.

In the bowl of your stand mixer, fitted with the paddle, beat the butter, sugar, salt, baking powder, and vanilla extract until smooth and creamy.

Add in the eggs, one at a time, until smooth and uniform.

Turn mixer to low and in flour, one cup at a time, and mix until smooth but sticky.

Scoop out the dough onto your baking sheet, and form into two flat, wide loaves, a couple inches apart. Wet hands and smooth the tops of the loaves.

Bake at 350f for 25 or so minutes until both loaves are set and starting to turn golden brown.

Remove loaves from the oven, and using a BBQ brush, lightly brush the crust of the loaves with warm water - this will reduce the crumbing later.

Allow loaves to cool for 5 or so minutes, and transfer to a cutting board. Slice the loaves crosswise into 3/4" slices. Return the slices to the baking sheet, laying flat, and bake for another 25-30 minutes.

Remove biscotti from pan and cool on a wire rack until room temperature.

Store in an airtight container!