Salted Caramel Cupcakes

Ingredients:

For the sponge:
70g unsalted butter, softened
170g plain flour
250g caster sugar
50g cocoa powder, sifted
1 tbsp baking powder
½ tsp salt
210ml (71/2fl oz) whole milk
2 large eggs

For the frosting:
670g icing sugar, sifted
210g unsalted butter, softened
70ml whole milk
30g tinned caramel or dulce de leche
Pinch of good-quality sea salt (such as maldon)

For the filling and decoration:
100g tinned caramel or dulce de leche
Pinch of good-quality sea salt

Method:

1. Preheat the oven to 170°C/gas mark 3, and line the muffin tins with paper muffin cases to make the number you require. First make the sponge. In a freestanding electric mixer with the paddle attachment or using a hand-held electric whisk, mix the butter, flour, sugar, cocoa powder, baking powder and salt together until they form a crumb-like consistency. In a jug, mix together the milk and eggs by hand.
2. With the mixer or whisk on a slow speed, gradually pour half of the liquid into the crumb mixture and mix thoroughly until combined. Raise the speed to medium and beat until the batter is smooth and thick, with no lumps. Scrape down the sides of the bowl now and then. Once all lumps are gone, turn the speed back down and gradually pour in the remaining liquid, continuing to mix until the batter is smooth and combined.
3. Spoon the batter into the prepared paper cases, filling them two-thirds full. Using a 50 millilitre ice-cream scoop can make this process easier and will result in even cupcakes. Bake for 20 to 25 minutes or until the sponge bounces back when lightly touched. Leave to cool slightly before removing from the tin and placing on a wire rack to cool completely before frosting.
4. Using the freestanding electric mixer with the paddle attachment or the hand-held electric whisk, gradually mix the icing sugar and butter together on a low speed until combined and there are no large lumps of butter. Gradually add the milk while mixing on a slow speed. Add the dulce de leche and sea salt and mix thoroughly. Turn up the speed and beat until light and fluffy.
5. Once the cupcakes are cool, use a sharp knife to make a hollow in the centre of each cupcake, approximately two centimetres in diameter and about three centimetres deep. Retain the cut-out piece of sponge. Spoon about 1 teaspoon of the dulce de leche into the hollow.
6. Replace the cut-out piece of sponge, trimming to fit and pressing down gently to ensure that the top is level with the rest of the cake.
7. Spoon generous amounts of the frosting onto each cupcake, then gently smooth over with a palette knife, making a swirl at the top if you wish. To finish, spoon about 1 teaspoon of dulce de leche on the top of each frosted cupcake, swirling it slightly into the frosting, and add a light sprinkling of sea salt.