Preheat the oven to 350F and line a 12count muffin tin with paper liners.

In a large bowl, whisk together the flour, sugar, and baking powder.

In another bowl, whisk together the milk, vegetable oil, eggs, and vanilla.

Add the wet ingredients to the dry and mix just until no lumps of flour remain.

Divide the batter between the muffin tins, filling each one ¾ of the way full with the batter.

Bake for 14-16 minutes, or until a toothpick inserted into the center comes out clean.

Remove the cupcakes from the pan and transfer them to a wire rack to cool completely.

Heat the milk in a small saucepan set over medium heat, just until it starts to steam.

In a small heat-proof bowl, whisk together the egg yolks, sugar, and cornstarch for 1 minute, or until they become pale yellow.

Next, slowly whisk in the milk, a little at a time. Make sure not to add it all at once or you may scramble the eggs.

Once all of the milk has been incorporated, return the egg mixture to the saucepan and set it over medium heat again.

Cook, stirring constantly, for 3-4 minutes or until the cream has thickened. It will be very thin and then thicken very quickly-- don’t stop stirring or it may burn.

Once the cream has thickened, remove it from the heat and add the vanilla bean paste and butter. Whisk to combine.

Transfer the cream to an airtight container and cover the surface with plastic wrap (make sure the plastic is directly touching the cream so it doesn’t form a skin).

Transfer the cream to the fridge and chill until it is no longer hot-- about 1 hour.

Add the butter and vanilla to the bowl of a stand mixer fitted with the paddle attachment.

Beat on medium speed until the butter is light and fluffy-- about 1 minute.

Next, sift together the confectioner's sugar and cocoa powder to remove any lumps.

With the mixer on low speed, slowly add the dry ingredients into the butter.

Once all of the dry ingredients have been incorporated, turn the mixer to high speed and beat until the frosting becomes light and fluffy-- about 1 minute.

Transfer the frosting to a piping bag fitted with your choice of tip and set aside until ready to use.

Add the heavy cream, chocolate chips, and coconut oil to a small microwave safe bowl.

Microwave for 30 seconds and stir. If the chocolate is not fully melted, microwave it for an additional 30 seconds and stir.

Whisk until the ganache is smooth. Set it aside to cool to room temperature before using. The ganache should be pourable but not warm (you don’t want it to melt the buttercream).

Scoop out the center of each cupcake and fill it with 2 teaspoons of pastry cream. Place the top of the cupcake back on to cover the creamy filling.

Pipe the chocolate buttercream on top and finish the top with a small drizzle of chocolate ganache.

Enjoy the cupcakes immediately or store them in an airtight container in the fridge for up to two days.

Bring to room temperature before enjoying again.