In a large mixing bowl, whisk together the 1 cup milk for the filling and the pudding mix until well combined; set aside to thicken. In a separate mixing bowl, beat the 1 cup heavy whipping cream until thick and soft peaks form, then mix in the 1/2 cup powdered sugar and 1 teaspoon vanilla extract. Fold the pudding mixture into the whipped cream. Cover and refrigerate the cream filling until you're ready to fill the donuts.

While the donuts are cooling, make the chocolate frosting. Add the 2 tablespoons milk, 2 tablespoons heavy whipping cream, and 2 tablespoons butter to a large saucepan over medium heat. Cook, stirring often, until the mixture begins to bubble. Turn off the heat and add the vanilla extract, corn syrup, and dark and milk chocolates. Set this aside and allow to sit for a few minutes for the chocolate to melt, then whisk well until smooth. Whisk in the 2 1/4 cups powdered sugar until well combined. Tip: if there are still lumps of powdered sugar in the frosting, turn on the heat to medium and keep whisking until the lumps have melted into the frosting.

Use a thick skewer, chopstick, or the end of a wooden spoon to make a hold in each donut from one end into the center. Scoop the cream filling into a piping bag or a condiment bottle with a tip that can fit into the hole in the donuts. Squeeze the cream into the donuts to fill as much as you can without it bursting through the other side.

Dip the top of each donut in the warm chocolate frosting, then place the donuts on a wire cooling rack until the frosting is set. Tip: be sure the donuts are fully cooled before filling and frosting.

Serve the donuts fresh.