Let’s walk through the process:

Make the Cupcakes:

1. Preheat and Prep: Preheat oven to 350°F (175°C) and line 2 standard 12-cup muffin tins with liners.

2. Cream Butter and Sugar: In the large bowl of a stand mixer fitted with the whisk attachment (or in a large bowl using an electric mixer), beat butter and granulated sugar on medium speed until light and fluffy.

3. Add Eggs and Extracts: Add eggs one at a time, beating well after each addition. Add vanilla and coconut extract (if using) and mix until combined.

4. Combine Dry Ingredients: In another large bowl, whisk together the flour, cornstarch, baking powder, and salt.

5. Combine Wet and Dry: Add half of the dry ingredients to the butter mixture and beat until just combined. Pour in the milk and beat until incorporated. Add the remaining dry ingredients and beat until just combined. Be careful not to overmix.

6. Fill Cupcake Liners: Fill the prepared cupcake liners three-quarters full with batter.

7. Bake: Bake until slightly golden on top and a tester inserted into the center comes out clean, about 25 minutes.

8. Cool: Transfer the cupcakes to a wire rack and let them cool completely.

Make the Custard Filling:

1. Whisk Milk and Pudding: In a medium bowl, whisk the coconut milk and instant vanilla pudding mix until no lumps remain.

2. Set and Chill: Let the mixture firm up at room temperature for 5 minutes, then refrigerate until ready to use.

Assemble the Cupcakes:

1. Create Wells: Using a melon baller or teaspoon, scoop out the center of each cooled cupcake to create a well about 1 inch deep. Cut off the tops of the removed pieces of cupcake and reserve; reserve the remaining pieces of cupcake for another use (like cake pops!).

2. Fill Cupcakes: Using a small spoon or a piping bag, fill each cupcake with the coconut pudding mixture.

3. Replace Tops: Close with the reserved top pieces from each cupcake. This will make them easier to frost.

Make the Frosting:

1. Beat Cream Cheese: In the large bowl of a stand mixer fitted with the whisk attachment (or in a large bowl using an electric mixer), beat the cream cheese on medium-high speed until creamy and smooth, about 1 minute.

2. Add Powdered Sugar: Add the powdered sugar and beat, scraping down the sides of the bowl with a spatula, until no lumps remain.

3. Add Cream and Salt: Reduce the mixer speed to low and add the cold heavy cream in a slow, steady stream. Add the salt and beat on high speed until stiff peaks form, about 2 minutes more.

4. Frost Cupcakes: Pipe or spoon the frosting onto the filled cupcakes.

5. Top with Coconut: Sprinkle with the toasted shredded coconut.