Preheat the oven to 375 degrees F (190 degrees C).

Place sesame seeds on an ungreased baking sheet and toast in the preheated oven for 10 to 12 minutes until light brown. Watch closely so that they don't burn.

Mix together brown sugar, flour, toasted sesame seeds, melted butter, egg, vanilla, salt, and baking powder in a large bowl until combined.

Drop dough by 1/2 teaspoonfuls, 1 1/2 inches apart, onto a lightly greased baking sheet.

Bake in batches in the preheated oven for 4 to 6 minutes, until light brown. Let cookies cool briefly before removing from baking sheets to a wire rack to cool completely.

Repeat Steps 4 and 5 to bake remaining batches.