Preheat oven to 350 degrees Fahrenheit (175 degrees Celsius).

Add cider vinegar to soymilk and set aside to curdle.

Sift flour, cornflour, baking powder, and baking soda together in a bowl.

In a separate bowl, whisk together the soymilk mixture, sugar, vanilla essence, and oil until foamy.

Add wet ingredients to dry ingredients and stir gently until just combined, leaving small lumps.

Pour batter into cupcake liners, filling them 2/3 full.

Bake for 20-25 minutes, or until golden brown.

Remove from oven and let cool completely.

Prepare the custard by mixing custard powder with 1 tablespoon of milk to form a paste.

Add remaining milk, sugar, and vanilla to the paste and mix thoroughly.

Microwave on high heat for 4 minutes, stirring halfway through, until thick and gloopy.

Adjust consistency with more milk or custard powder as needed.

Taste and adjust sweetness/vanilla flavor.

Cover and set aside to cool.

To assemble, use the end of a teaspoon to create a hole in the center of each cupcake.

Enlarge the hole by pushing around the edges with your finger.

Fill the hole with raspberry jam using a pastry bag with a thin nozzle.

Rinse and refill pastry bag with custard and a star-shaped nozzle.

Pipe custard swirls over the jam hole on each cupcake.

If serving immediately, place a mini jammy dodger on top of the custard swirl. Otherwise, add just before serving.