This is a recipe good enough to have been reproduced on two baking blogs. I used the version from here, primarily because the measurements are British - in grams and cups - thank goodness! Converting a recipe from American measurements to British isn't difficult but if someone has already done the work for you, why reinvent the wheel?
I've tried a couple of blueberry muffin recipes before but this is my favourite so far. It's a bit more trouble than the usual - having to do the crumb topping in Singapore isn't easy unless you have a food processor - but it yields crumbly fragrant muffins liberally studded with jammy fruit. I promise you, with 250 grams of blueberries in them, you'll get blueberries with every bite. I hate buying "blueberry" muffins from shops only to find that there are maybe two blueberries in the entire muffin. The worst offenders are those that promise blueberries only to give you some kind of reconstituted blueberry jam and flavouring.
The real secret to this recipe is the browned butter. If you've never tried browning butter, please please try it out now. The smell alone makes the whole process worth it. If you don't know how, here is a simple step by step guide with picture. Try it out, because what isn't in the pictures is how it releases this incredibly delicious nutty fragrance that fills the entire house and makes you all happy. Also these muffins keep well too - about 3-4 days in an airtight container?
Brown Butter Blueberry Muffins
For the muffin mix:
90ml whole milk
1 egg yolk
1 tsp vanilla essence
175g plain flour
170g caster sugar
1 1/2 tsp baking powder
pinch of salt
Preheat the oven to 190C/375F. Put muffin liners in a muffin tin. Melt the butter in a medium saucepan. Keep heating it over medium heat until it has foamed up and brown bits have appeared and it smells nutty and delicious. Make sure you keep an eye on it as it happens - it takes a while but can burn quickly. Take off the heat and leave to cool slightly.
Whisk the egg, egg yolk, milk and vanilla together, then add the brown butter and whisk again. Put the flour, sugar, baking powder and salt in another bowl and combine. Pour the liquids into the bowl and fold in until just combined. Fold the blueberries in. Spoon out into the muffin cups.
For the crumble topping:
80g golden caster sugar
Measure out all the ingredients into a small bowl. Rub together until you have a crumbly mixture. OR process in a food processor until you have a crumbly mixture. Divide between the muffins. Put into the oven and bake for around 20 minutes, until they are lightly browned and a toothpick comes out clean. Leave to cool on a wire rack for a bit before eating.
Note: I used normal castor sugar for the crumble topping and it was fine. If you don't want to specially buy golden castor sugar for this, you can mix in a few teaspoons of brown sugar with normal castor sugar.