Preheat the oven to Gas Mark 4, 180°C, fan 160°C. Line a 12-hole muffin tin with 9 cupcake cases. Put the butter and sugar into a bowl and whisk until light and fluffy. Gradually add the eggs, beating between each addition. If the mixture splits, add a tablespoon of flour and whisk until the batter is smooth. Sift the flour into the mixture and using a large metal spoon, then gently fold the flour until well combined. Stir in the vanilla essence and milk. The mixture should easily drop off a spoon. Spoon into the cases and cook for 18-20 minutes or until a skewer comes out clean when inserted into the cake. To make the buttercream icing, put the butter in a large bowl and beat until creamy. Sift in the icing sugar and whisk until well combined. Add the vanilla extract. If the mixture is too stiff, add a little milk. Cut the top off each cake and then cut the slices in half. Cover each cake with the butter icing. Put a little strawberry jam on top of each cake and push the 2 half-slices into the buttercream at an angle to make a pair of wings. Dust with icing sugar and serve.