I have baked these muffins in different variations a few times now and can really recommend the recipe.
This time I added 125 g blueberries and one banana which I cut into little pieces. Take out one heaped teaspoon of the flour and mix into your fruit. This will prevent it sticking together all in one lump. As I hardly eat any dairy products these days I used almond milk which worked and tasted great, too.
Make sure to look through the blue berries for any small stalks which might still be there. I always like to add 1 teaspoon of vanilla extract as well or substitute some sugar with homemade vanilla sugar.
The recipe makes 24 muffins if you use the paper liners. I like to use the higher and more sturdy paper boxes so the recipe made 13 muffins. Every oven bakes differently, mine baked 25 minutes on 200°C (upper/lower heat).
Yummy, one teaspoon left for me.
Recipe: http://www.bbcgoodfood.com/recipes/2331641/basic-muffin-recipe