Preheat oven to 300° F.
In a medium bowl combine flour, cocoa, soda and salt. Mix well and set aside. Blend sugars in a large bowl using an electric mixer set at medium speed.
Add butter and mix to form a grainy paste, scraping down sides of bowl.
Add eggs and vanilla, and beat at medium speed until smooth. Add the flour mixture and chocolates, and blend at low speed until just combined.
Drop by rounded tablespoon onto ungreased cookie sheets, 2 inches apart. Bake 23-25 min. Transfer to cooling rack.Makes 36 Dozen Source: