Unlike other recipes, this one uses a custard filling instead of peanut butter. Deep-frying is the classic method to cook it, but air-frying also works. I've included instructions for both!
In a medium bowl, whisk together the sugar, flour, cornstarch, and egg.
In a small saucepan, bring the milk to a boil. Gradually add the milk to the egg mixture and whisk constantly until smooth. Pour the liquid back into the saucepan and whisk constantly until it boils and thickens. Remove from the heat and stir in the butter and vanilla extract.
Grab 3 slices of bread. Spread a thin layer of the custard filling between each slice and sandwich them together.
In a shallow dish, whisk together the eggs and milk.
Coat the sandwich in the egg wash, then deep fry at 350°F until golden brown or spray with oil and air fry at 400°F for 8 minutes, flipping once in between.
Transfer to a plate and drizzle on sweetened condensed milk. Enjoy!
Notes
*The recipe makes enough custard for 2 batches of this recipe. I couldn't make any less because you need one full egg to make the custard.