Preheat your oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.
Prepare the yellow cake mix according to the package instructions, mixing in the eggs, oil, and water. Pour the batter evenly into the prepared pans.
Bake for 25-30 minutes or until a toothpick inserted into the center comes out clean. Let the cakes cool in the pans for 10 minutes, then turn them out onto wire racks to cool completely.
While the cakes cool, prepare the vanilla pudding according to package instructions, adding vanilla extract.
Whip the heavy cream until soft peaks form and fold it into the cooled vanilla pudding.
Once the cakes are completely cool, place one layer on a serving plate and spread the vanilla cream filling over the top. Place the second cake layer on top.
Pour the chocolate ganache over the top of the cake, allowing it to drip down the sides.
Dust with powdered sugar if desired and refrigerate for at least 1 hour before serving. Enjoy your impressive Boston Cream Pie!