Preheat oven to 180 C temp.
In a small bowl, combine the flax seeds and 6 tbsp water. Keep for about 5 min.
In a big bowl, add the banana, tahini, milk, oil, maple syrup, sugar, vanilla extract, flax seeds. Mix until combined.
In another bowl, add the flour, salt, baking powder. Add them to the wet ingredients bowl. Mix until combined.
Add the frozen raspberries. Incorporate into the mixture.
Divide the batter between 12 muffin tin. Sprinkle with sesame (optional).
Bake for about 30 min.