Line a 13x9-inch baking pan with foil or parchment paper, extending over edges. In a food processor place graham crackers, coconut, and pecans; cover and pulse until fine crumbs form. Transfer to a large bowl.

In a small heavy saucepan heat 1 cup of the butter, the cocoa, and granulated sugar over medium until butter melts and mixture just comes to a simmer.

Meanwhile, in a small bowl lightly beat eggs. Gradually whisk about ½ cup of the hot butter mixture into the eggs. Whisk egg mixture into remaining butter mixture in saucepan. Cook, whisking constantly, until thick, about 30 seconds. Remove from heat. (Mixture may separate.)

Stir chocolate mixture into graham cracker mixture in bowl until combined. Press evenly and firmly into bottom of prepared pan with your fingers or the bottom of a measuring cup. Chill while preparing pudding layer.

In a large bowl beat remaining 1 cup butter, the heavy cream, and pudding mix with a mixer on medium until fluffy. Gradually beat in powdered sugar until smooth. Evenly spread over the crumb layer in pan. Cover and chill 30 minutes.

Meanwhile, in a medium bowl microwave chocolate chips and shortening until melted, 1 to 2 minutes, stirring every 30 seconds. Spread chocolate mixture evenly over chilled bars. Refrigerate until set, about 30 minutes.

Once chocolate is set, lift uncut bars from pan using foil or parchment. Transfer to a cutting board and cut into square or rectangle bars. Refrigerate in an airtight container up to 3 days. If you like, just before serving, dust with additional powdered sugar.