In a bowl, whisk together the egg yolks and sugar until well combined.

Add the cornstarch and mix until smooth.

In a saucepan, heat the milk and vanilla paste until small bubbles form around the edges. Do not boil.

Gradually add the hot milk to the egg mixture, stirring constantly to temper the eggs.

Return the mixture to the saucepan and cook over medium heat, stirring constantly, until the custard thickens (it should come to a full boil to activate the cornstarch).

Transfer the custard to a bowl, cover with plastic wrap, and cool in the refrigerator or set outside to chill.

In a large bowl, whisk together the eggs, sugar, and salt.

Gradually add the milk, mixing until combined.

In a separate bowl, sift together the flour and baking powder.

Add the dry ingredients to the wet ingredients and mix until smooth.

Stir in the oil.

Preheat your wheel cake pan over low heat.

Lightly oil the pan using a paper towel to ensure easy release.

Pour the batter into each divot, filling them about halfway.

Add a spoonful of vanilla custard or red bean paste into the center of each divot.

Carefully pour more batter on top to cover the filling.

Cook on low heat until the cakes are golden brown and cooked through, about 3-4 minutes per side. You may need to flip them to ensure even cooking.

Remove the wheel cakes from the pan and let them cool slightly before serving.

Enjoy warm with a cup of coffee or tea!