Peanut Butter Muffins

• 2 bananas, ripe large
• 1 egg
• .5 cup maple syrup
• .5 cup peanut butter
• 1 tsp baking powder
• 1 tsp baking soda
• .25 tsp salt
• 2 tsp vanilla extract
• .5 cup crushed nuts
• 1.75 cup wholemeal flour or oat flour
• .5 cup milk
• .5 cup plain greek yoghurt