Preheat oven to 180°C. Line 20 muffin tins with cupcake papers.

Cream the butter and sugar with an electric mixer until light and fluffy in a large bowl.

Add the eggs one at a time, beating well after each addition. Add vanilla and mix. Combine flour, baking soda and baking powder in a separate bowl, set aside.

In another bowl, whisk together the champagne and sour cream.

Add flour and champagne mixture alternately, beginning and ending with flour.

Fill cupcake liners about ¾ full with mixture and bake for 15-17 minutes until lightly golden brown.

Allow to cool in the tin for 15 minutes, then turn out onto a wire rack.

Finely chop strawberries and place in a small saucepan over medium heat.

Add in lemon juice, cornstarch and icing sugar and let bubble over the heat for 5 minutes, stirring often.

Remove the mixture from the heat and allow to cool, if it's still a bit chunky then squash with a potato masher.

Make a small cross with a sharp knife in the top of each cupcake. Pour strawberry filling into a piping bag with small nozzle attached and pipe cooled strawberries into each cupcake.

Simmer champagne over medium-high heat in a small saucepan until reduced to 2 tablespoons. Transfer to a small bowl and allow to cool completely.

Place the softened butter in a large mixing bowl and beat until smooth.

Gradually add in 4 cups of sugar until thick and fluffy.

Pour in the reduced 2 tablespoons of champagne and continue mixing for another few minutes.

Taste the icing, if you feel it needs a little more champagne flavour then add in another tablespoon straight from the bottle (no need to reduce it). Mix well afterwards.

Spoon the mixture into an icing bag with a nozzle attached and ice the cupcakes.