Preheat the oven to 350°F (175°C) and line muffin tins with paper liners.
For the batter, whisk together the flour, baking powder, pudding mix, and salt in a medium bowl until evenly combined.
1½ cups (190 g) all-purpose flour, 1 tsp (4 g) baking powder, 1 box (3.4 oz / 96 g) instant vanilla pudding mix, ¼ tsp (1 g) table salt
In a large bowl, beat the butter and sugar until light and fluffy. Add the eggs one at a time, mixing well after each, then blend in the vanilla extract.
½ cup (113 g) unsalted butter, ¾ cup (150 g) granulated sugar, 2 large eggs, 1 tsp (5 ml) vanilla extract
Alternate adding the dry ingredients and the buttermilk to the butter mixture, beginning and ending with the flour. Mix until just combined.
1 cup (240 ml) buttermilk
Divide the batter evenly among the cupcake liners, filling each about two-thirds full. Bake for 18 to 20 minutes, or until a toothpick inserted in the center comes out clean.
Cool the cupcakes completely on a wire rack. Once cooled, use the end of a piping tip or a small knife to cut a small circle from the center of each cupcake for the filling.
For the vanilla cream layer, whisk together the pudding mix, whole milk, and vanilla until smooth and thickened. Refrigerate for about 10 minutes, then pipe or spoon the pudding into the hollowed cupcakes, rounding it slightly on top.
2 boxes (5 oz /142 g each / 284 g total) instant vanilla pudding mix, 4 cups (960 ml) whole milk, ½ tsp (2.5 ml) vanilla extract
Place the filled cupcakes in the freezer for 30 minutes to help the cream firm up before adding the ganache.
For the ganache, combine the chocolate chips and cream in a microwave-safe bowl. Heat in short bursts, stirring each time, until the chocolate melts and the mixture turns glossy and smooth.
1½ cups (270 g) semi-sweet chocolate chips, 1 cup (240 ml) heavy cream
Spoon or pour the ganache over the chilled cupcakes, letting it settle into an even layer. Refrigerate for about 30 minutes, just until the ganache sets with that signature Boston Cream shine.