With a sharp butcher knife, cut whole roasted almonds in half. Some will break into smaller pieces which, is fine. Set aside.
In a large mixing bowl, cream the butter and sugar (combine and mix until almost smooth.) Add one egg at a time. Scrape the sides of the bowl. Stir in almond extract and lemon zest. Add the baking powder, salt and flour. Continue mixing until smooth. Stir in cut almonds. Refrigerate dough for 1 hour.
Preheat oven to 375F.
Grease a baking sheet. Divide cooled dough into two. Form two 10 inch or so logs spaced at least 2 inches apart. Bake for 25 min. Allow them to cool completely before you cut them.
Preheat oven to 350F.
With a large serrated knife, cut the logs into 1 inch wide pieces. Place the pieces flat on two un-greased baking sheets. Bake 8 min. Flip the biscotti over and bake another 8-10 min or until lightly browned. Cool completely.
Line a baking sheet with wax paper. In a microwave safe bowl, melt semi sweet chocolate chips in microwave for about 30 seconds. Stir and microwave again for 30 more seconds or until melted when stirred. Dip flat end of biscotti into melted chocolate. Put chocolate-dipped biscotti onto wax paper to harden.
Store biscotti in an airtight container up to 2 weeks. You may also freeze the doughor the biscotti after they're baked and cooled for up to six months.