Preheat oven to 300 F. In a medium bowl combine flour, cocoa, soda and salt. Mix well with a wire whisk and set aside. In a small bowl dissolve coffee crystals in coffee liqueur and set aside. In a large bowl blend sugar with an electric mixer at medium speed. Add butter and mix to form a grainy paste. Scrape down sides of bowl. Then add eggs and dissolved coffee crystals, and beat at medium speed until smooth. Add the flour mixture and chocolate chunks, and blend at low speed just until combined. Do not over mix. Drop by rounded tablespoonfuls onto ungreased cookie sheet, 2 inches apart. Bake for 23 to 25 minutes. Immediately transfer cookies with a spatula to a cool, flat surface.