
Preheat oven to 400 degrees Fahrenheit.
In a medium bowl, whisk together the yogurt, egg, and any additional add-ins of choice until smooth.
Place bread slices on a lined baking sheet. Using your hand or the back of a spoon, make a dent in the center of each slice of bread. Be careful not to tear and leave about ½ inch on all sides.
Spoon the custard filling on top and add toppings of your choice.
Bake in the regular oven or the toaster oven until the custard the sets and the bread gets nice and toasty, about 10-12 minutes.