Used the recipe from Happy Home Baker, but substituted with mini chocolate and butterscotch chips that I have in the refrigerator.
The result is rather delightful, thanks to abundance of chocolate and butterscotch chips. The muffin itself was a little dry. As for the 'crumble', I must have put in too much butter because its not crisp as I thought it should be. But it does make the muffin look more asthetically pleasing.
Here's the recipe :
Chocolate/Butterscotch Chips Crumble Muffins
250g self-raising flour
1 teaspoon baking powder
a pinch of salt
100g soft light brown sugar
150g chocolate chips
2 eggs, lightly beaten
2 teaspoons vanilla extract
for the Chocolate Crumble Topping:
50g plain flour
1 tablespoon unsweetened cocoa powder
2 tablespoons caster sugar
For the chocolate crumble topping, sift flour and cocoa powder into a bowl. Mix in the sugar and rub in the butter until the mixture resembles coarse breadcrumbs. Set aside.
Mix flour, baking powder and salt in a mixing bowl. Rub in the butter until the mixture resembles breadcrumbs. Stir in the sugar and the peanut butter chips.
In another bowl, mix eggs, milk and vanilla extract. Pour the liquid mixture all at once into the dry ingredients. With a wooden spoon or spatula, mix until just combined. Do Not Over Mix. The batter should remain lumpy.
Fill paper muffin cups with batter sprinkle with the crumble toppings. Bake in a preheated oven at 200degC for 18-20mins, or until well risen and firm to the touch. A skewer inserted into the centre should come out clean. Let cool completely.
Recipe source: adapted from Muffins Galore, Catherine Atkinson