In small bowl blend flour, cocoa and baking soda. Mix until well blended.
In large bowl beat white and brown sugars, butter or margarine and 1/4 cup peanut butter, until light and fluffy. Add vanilla and egg, beat. Stir in flour mixture until blended. Set aside.
To make Filling: Combine confectioner’s sugar and 3/4 cup peanut butter. Blend well.
Roll filling into 30 1-inch balls. For each cookie, with floured hands, shape about 1 tablespoon of dough around 1 peanut butter ball, covering completely. Place 2 inches apart on an ungreased cookie sheet. Flatten with glass dipped in white sugar.
Bake at 375 degrees F (190 degrees C) for 7-9 minutes. When cookies are done, they should be set and slightly cracked.