Position rack in center of oven; preheat to 350 degrees. Line three large cookie sheets with kitchen parchment or nonstick silicon sheets, or grease them. Set aside. In a large bowl, whisk together flour, salt and salt. Set aside.

Melt bittersweet chocolate (in microwave or double boiler on stovetop); set aside to cool to barely warm. Chop semisweet chocolate into small bits. Set aside.

In a stand mixer (or large bowl with hand-held mixer), beat butter, brown sugar, cocoa, orange zest and vanilla. Add eggs one at a time, beating. Add chocolate and mix 1 minute. Add flour mixture and mix on low speed 1 minute. Add chopped chocolate and mix 15 seconds.

Sprinkle sugar on flat plate. With small ice-cream scoop or rounded spoon, form 1 1/4-inch balls (batter will be soft, oily). Dip one side of each ball in sugar and place, sugar side up, on cookie sheet, about 1 1/2 inches apart.

Bake one sheet at a time until cookies puff and crackon top, 11 to 12 minutes. Cool on cookie sheet 5 minutes; transfer to racks. (Cookies crumble if moved too soon, soften if left too long.)

Makes about 60 cookies.

Send recipes and queries to Wanda A. Adams, Food Editor, Honolulu Advertiser, P.O. Box 3110, Honolulu, HI 96802. Fax: 525-8055. E-mail: wadams@honoluluadvertiser.com.

For more information about our 150th anniversary cookbook, call 535-8189 (message phone; your call will be returned). You can order the cookbook online.