*This recipe slightly modified from the original as noted.

Preheat oven to 325 (was: 400) degrees F. (was: Until you are ready to assemble the cookies just prior to baking, keep the marshmallows in the freezer-otherwise they will thaw too rapidly - changed to: Use fresh marshmallows Only).

In medium bown combine flour, cocoa and baking soda. Set aside.

Combine sugars in a large bowl. Using an electric mixer, blend in butter, scraping down the sides of the bowl. Add eggs and vanilla, and beat at medium speed until light and fluffy.

Add the flour mixture and chocolate chips, and blend at low speed until combined. Batter will be very stiff.

Gather 4-5 (was: frozen) marshmallows in the palm of your hand and cover them with a heaping tablespoonful of dough. Wrap the dough around the marshmallows, completely encasing them and forming a 2-inch-diameter dough ball.

Place balls on ungreased baking sheets, 2 inches apart. Bake 15 (was 20-22) minutes. Cool on pan 2 minutes, then transfer to a cool, flat surface.