In double boiler over hot water, melt bittersweet chocolate chips and butter.
Place eggs and sugar in mixer bowl. attach bowl and flat beater to mixer. Turn to speed 4 and beat until thick. Reduce to stir speed and add chocolate mixture. mixed until combined, then stop and scrape bowl.
Stir flower and baking powder together in small bowl. Continuing on stir speed, add flour mixture and semi-sweet chocolate chips and walnuts and mix until a thick dough forms.
Using sheets of plastic wrap, form dough into two logs, each 2 inches long in diameter and about 12 inches long. As dough will be quite soft, use plastic wrap to hold in log shape. wrape tightly; refrigerator at least one hour or until firm.(dough can also be frozen; thaw in refrigerator before proceding with recipe.)
Heat oven to 375 degrese. unwrap dough; with sharp knife, cut into 3/4 inch slices. places slices
1 1/2 inches apart on greased cookie pan.
Baked 12 to 14 minutes or until shine crust forms on top but interior is still soft.
cool on baking sheet; Store in air tight tin up to one week. And enjoy