Crumbly blueberry muffins.

Hi guys- I followed this recipe (http://ift.tt/1SZcmmZ) to the letter to make some blueberry muffins. They were delicious!

However, they were too crumbly and fell apart easily. Is there anything i can do to make them more firm without changing the taste i get from the recipe? These are perfect despite falling aprt easily.

bon appetit