Beat the eggs until combined; stir in the melted butter. Add the water, pudding mix, and yellow cake mix, stirring well to combine.
The batter will be very thick. Divide the batter between the prepared pans, spreading it evenly.
Bake until the cakes spring back when pressed lightly with a finger or a tester comes out clean, 15 to 20 minutes. Cool completely on wire racks.
Twinkie Filling Instructions
To make the filling, combine the room-temperature butter, cream cheese, and confectioners' sugar. Beat until smooth. Stir in the whipped topping and vanilla extract.
I used the injector kit that comes with the Norpro 3964 Cream Canoe Pan to fill each of the cakes