Cut the bread slices into even cubes and place in a bowl.
Beat the sugar and eggs until frothy, add the vanilla extract and cinnamon. Add the milk while stirring.
Pour the mixture over the toasted bread cubes and mix well, adding 1 - 2 more slices of toast if necessary. The egg mass must be used up. Then let the mixture steep for a short time until the bread has absorbed the mass.
Grease a muffin tin well with soft butter. I wouldn`t use muffin cups because the French toast muffins won`t get that crispy on the outside. When they come into direct contact with the muffin tin, they develop a tender crust.
Pour the toast egg mixture into the 12 hollows of the muffin tray. Since the mass does not rise, you can easily fill the hollows upwards.
Bake in a preheated oven for 25-30 minutes until golden brown. Let cool down slightly.
Then carefully remove the muffins from the muffin tray with 2 forks, place on a plate and serve with fresh fruit (e.g. sweetened strawberries) and / or maple syrup.