Combine all the ingredients to make the milk custard: all-purpose flour, granulated sugar, sweetened condensed milk, vanilla powder, salt, egg yolk, and water. Mix well until smooth.

Cool the cooked custard. Once cooled, take one cracker and spread the milk custard on top. Smooth it out, then sprinkle with cheese (if you don't like it salty, you can skip the cheese or reduce the salt). Cover with another cracker and repeat until all the custard is used.