Preheat the oven to 350°F.
1) Beat the butter and sugar until fluffy.
2) Add the salt, baking powder, malted milk, and flavorings, beating until blended.
3) Beat in the egg and yolk.
4) Blend in the flour.
5) Scrape the sides and bottom of the bowl, then add the white chocolate and nuts.
6) Scrape the dough onto a lightly greased or parchment-lined baking sheet, and shape it into a log about 16" x 2 1/2". Or scoop the dough into a biscotti pan, shaping a rough log, and leaving about 3/4" bare around the edges of the pan.
7) Bake the dough for 32 to 36 minutes.
8) Remove from the oven, and cool for 45 minutes or more.
9) Cut into 1/2" diagonal slices. Place them onto baking sheets, standing them on edge.
10) Reduce the oven heat to 325°F, and bake for an additional 25 to 35 minutes, until golden brown.
11) Remove from the oven, and cool right on the baking sheet.
12) When completely cool, wrap well for storage.