Blueberry Muffins with Crumb Topping

RY bought a box of blueberry and I used it to bake some blueberry muffins but to add a twist to it, I've added crump topping.

Recipe

Muffins

Ingredient A

Plain flour 220g

Baking powder 1tsp

Baking soda 1tsp

Salt 1/2 tsp

Cold butter 80g

Ingredient B

Egg 1

Milk 100ml

Sugar 80g

Vanilla essence 1tsp

Blueberry 120g (leave some to sprinkle)

Raisin a handful (optional)

Method

1 mix ingredient A and B separately in different bowl

2 add in cold butter in A using rubbing in method

3 mix B into A gradually with minimum stroke, then fold in blueberry and raisin till mixture is lumpy and thick which is spoonable

4 scope into muffin cups till 90% full then coat the crumb topping and sprinkle the blueberry 

Yield 10 muffins

Crumb Topping Ingredient 

1 tsp flour

2 tsp brown sugar

1 tsp butter

1/4 cinnamon powder

1/4 nutmeg powder

Mix the above and leave aside (if want more crump topping, can increase the ingredient portion)

Update : to make 18 muffins

Dry ingredient 

Plain flour 300g

Baking soda 1 tsp

Baking powder 1 & 1/3 tsp

Salt 1/4 tsp

Blueberry 180g (leave some to sprinkle)

Wet ingredient 

Butter 110g

Eggs 2

Milk 140ml

Sugar 110g

Vanilla extracts 2 tsp