Caramel Apple Cupcakes with Salted Caramel Buttercream

Caramel Apple Cupcakes from Crazy about cupcakes
1 cup firmly packed light brown sugar
1/2 cup vegetable oil
2 teaspoons ground cinnamon
1 tablespoon vanilla extract
2 large eggs
2 cups flour 1 tablespoon baking powder
1/2 teaspoon salt
2 medium sized tart apples, peeled, cored and chopped small

Caramel filling
1/2 cup packed light brown sugar
55g butter
1/4 cup heavy cream
1 teaspoon vanilla extract

Salted Caramel Buttercream 
125g caster sugar
80ml double cream
1/2 teaspoon salt (to taste)
1 teaspoon vanilla extract
160g salted butter, softened
200g icing sugar, sifted

For the cake


Preheat the oven to 180C.In a large bowl, beat together the brown sugar, oil, cinnamon and vanilla with an electric mixer on medium speed.  Add the eggs one at a time. Beat for 1 minute after each addition. In a separate bowl, sift together the flour, baking powder and salt. Slowly add the dry mixture to the wet mixture. Beat until well blended.Stir in the apples.Fill the cupcake liners to 3/4 full and bake for 20-25 minutes.Leave to cool in the pan.

For the filling

In a saucepan over medium heat bring the brown sugar, butter and cream to a boil. Reduce heat to a simmer and continue stirring for 5 minutes.Remove from heat.Stir in the vanilla extract.

For the buttercream

To make the caramel, dissolve the sugar and 60ml water in a small, solid-based pan over a gentle heat, then increase the heat to a boil.Wait a few minutes, leaving the pan undisturbed but watching it like a hawk and, as soon as it changes to a wonderful caramel colour (like strong tea) and is thicker, remove immediately from the heat.Stand well back and add the cream.Be very careful as it's searing hot and may splatter a little.it will reach or 'seize' and you may think it has gone wrong; it hasn't.Keep stirring, adding the salt and the vanilla.Leave until stone cold.For the buttercream icing, cream the butter and icing sugar for at least 5 minutes.Add the caramel.