Preheat oven to 350 degrees F. Adjust oven racks; one in upper third of oven and one in lower third. Line two large baking sheets with parchment paper; set aside. In small bowl stir together flour, baking powder, and salt (flour amount may seem low but is correct); set aside.
In microwave-safe bowl combine chocolate and butter. Melt at 50 percent power (medium) about 2 minutes. Stir frequently until chocolate is almost melted. Remove. Stir to complete melting; set aside.
In medium heatproof bowl whisk together eggs, sugar, and vanilla. Place skillet 1/4 full of barely simmering water. Gently whisk 2 minutes or just until warm (about 100 degrees F). Stir egg mixture into melted chocolate. Stir in flour mixture until combined. Stir in walnuts and 6 oz. chopped chocolate. Fold in candied orange peel.
Spoon lightly rounded tablespoonfuls 1-1/2 inches apart on baking sheets. Bake, on separate racks, 8 to 10 minutes or until cookie surface appears dry, set, and slightly lighter in color (centers will be gooey), exchanging sheets to opposite rack halfway through baking. Slide parchment paper with cookies onto wire racks to cool completely. Makes 30 to 36 cookies.
Candied Orange Peel
Cut peel from oranges lengthwise in quarters, cutting just through pulp to surface of fruit. Pry back quartered peel with spoon. Scrape away soft white pith inside peel. Cut peel in 1/2-inch-wide strips. In a 2-quart saucepan combine 1 1/3 cups sugar and water. Bring to boiling; add orange peel. Return to boiling, stirring constantly to dissolve sugar; reduce heat. Boil gently, uncovered, for 15 minutes or until peel is almost translucent, stirring occasionally. Remove peel from syrup, allowing excess to drip off. Place on parchment or waxed paper. Cool until easy to handle (do not cool completely). Roll in 1 to 2 tablespoons sugar to coat. Let dry 1 to 2 hours. Coarsely chop peels. Makes about 1/3 cup.