Heat oven to 425 degrees F.
Whisk olive oil, tahini and brown sugar together in the bottom of a large bowl.
Whisk in eggs, then buttermilk and vanilla.
Whisk in baking powder, baking soda and salt.
Switch to a spoon or flexible spatula and stir in flour, then carrots, mixing just until combined.
Either line a 12-cup standard muffin pan with paper liners or coat them with a nonstick spray.
Fill each about ¾ of the way with batter.
Bake muffins for 14 to 16 minutes, or until a tester inserted into the center of each comes out batter-free.
Let them cool in pan for 5 minutes on a rack before transferring them to the cooling rack to cool completely.
If you’d like to glaze your muffins, whisk powdered sugar, tahini and water together in a medium dish.
Either drizzle this over the cooled muffins or dunk them into the puddle.
Sprinkle with sesame seeds, if desired.