Have 4 slices of bread ready on a clean work surface.
In a small bowl, add tahini sesame paste, black sesame powder and honey and stir until combined.
Spread half of the black sesame mixture onto one slice of bread and top with the other slice of bread.
Repeat with the remaining bread.
In a shallow bowl, whisk together eggs, milk, vanilla extract, sugar, and melted butter.
Soak one sandwich into the egg mixture and flip to soak on the second side.
Heat up a large skillet or frying pan over medium heat.
Add 1 teaspoon of butter to the pan.
Place the custard-soaked sandwich into the pan and cover with a lid.
Turn down the heat to medium-low and cook for 2-3 minutes, and flip to cook on the other side for another 2-3 minutes, or until golden brown.
Remove French toast from the pan and repeat with the remaining sandwich.
Drizzle with condensed milk and sprinkle black sesame seeds before serving.