In a large bowl sift together flour, tartar, baking soda, and salt. In another bowl beat together butter and sugar, then beat in brown sugar and corn syrup untill well blended. Beat in eggs one at a time and then vanilla. Gradually beat in the flour mixture. Stir in chocolate chunks.
Chill dough for at least 30 minutes! Drop dough by tablespoon onto greased cookie sheets and bake for 9-12 minutes.