Preheat the oven to 200 °C, 400°F, Gas 6. Arrange 8 – 12 paper cases in the muffin baking tin.
Sift the flour, sugar and baking powder into a mixing bowl.Whisk together the egg, milk, oil and vanilla. Stir in the dry ingredients until combined.
Spoon the mixture into the paper cases and bake for 20 minutes until golden brown. Cool in the tin for 5 minutes.
To make the toffee sauce
During baking time, heat the sugar and water in a high pan over low heat until the sugar has dissolved and starts to brown. You do not need to stir. Continue cooking, and again do not stir, until the sugar turns a golden amber.
Slowly pour the cream into the pan. It will bubble up but not enough to spill over the edge of the pan. Stir until well combined. Let cook for half a minute, stirring and turn off the heat.Set aside to chill.
Making the buttercream
Cut the butter at room temperature into small bites and mix with the powdered sugar. Beat with the hand or mixer until soft anf fluffy.
Now spoon in the caramel sauce and mix well.
Top every baked cupcake with buttercream using a piping bag. Drizzle with caramel sauce and serve.