1. Preheat oven to 375 degrees F (190 degrees C). 2. If your sesame seeds are not toasted, place them on an ungreased baking sheet and toast for 10–12 minutes or until they turn light brown. 3. They may burn easily, so watch closely to prevent this from happening. 4. Mix the brown sugar, melted butter, egg, vanilla extract, flour, salt, baking powder, and toasted sesame seeds together until well combined in a large mixing bowl. 5. Drop cookie dough by half-teaspoonfuls onto greased baking sheet. Make sure that at least 2 inches separate them; they spread A LOT. 7. Let them sit for 2–3 minutes.