Back when Ann K. Couwenhoven was studying mechanical engineering at Purdue University, she'd often make chocolate chip cookies because the caffeine in the chocolate helped her stay awake. True to her engineering background, she's been tweaking the recipe for years — adding walnuts or Grand Marnier and tinkering with the amounts of eggs, sugar and butter. ("Never use salted butter in cookies!") After dozens of iterations, the Monkton resident now has a fabulous recipe for Mocha Toffee Keks (that's cookies for non-German speakers). "If you like dark chocolate and coffee and toffee, you'll like this cookie," she says. "This is like a cookie version of Heath bars but darker."
Preheat oven to 350 degrees. Combine butter and baking chocolate in a microwave-safe bowl.Microwave the butter and chocolate, stirring occasionally until melted. Stir in coffee crystals; cool for about 5 minutes; set aside.
Combine flour, baking powder and salt in small bowl; set aside. Beat eggs in large bowl until thick and lemon-colored. Gradually add sugars, beating well after each addition. Add cooled chocolate mixture and vanilla; beat until well mixed. Reduce speed to low; add flour mixture. Blend until well mixed. Stir in chocolate chips and toffee pieces. Drop dough by heaping tablespoon, 2 inches apart, onto greased cookie sheets. Bake for 8 to 10 minutes or until set. Cool 5 minutes on cookie sheets; remove to wire cooling rack. If desired, drizzle with melted milk chocolate; let stand until chocolate is set.