Preheat oven to 180°C. Line eighteen 1/3 cup (80ml-capacity) muffin pans with paper cases.
Use an electric mixer to beat the butter, sugar and vanilla in a bowl until pale and creamy. Add the eggs, 1 at a time, beating well after each addition. Add the flour and milk, in alternating batches, until just combined.
Spoon the mixture evenly among the lined pans. Use the back of a spoon to smooth the surface. Bake for 20 mins or until a skewer inserted in the centres comes out clean. Transfer to a wire rack to cool completely.
To make the buttercream, use an electric mixer to beat the butter in a bowl until very pale. Gradually add the icing sugar, in batches, beating well after each addition. Add the milk and vanilla and beat until well combined.
Use a small sharp knife to cut a cone-shaped piece from the top of each cupcake, about 4cm wide and 1.5cm deep. Cut each cone-shaped piece of cake in half to form 2 semicircles.
Place the 100’s & 1000’s on a small plate. Place half the buttercream in a piping bag fitted with a 1cm-diameter fluted nozzle. Spread the remaining buttercream over the top of each cupcake. Dip each cupcake into the 100’s & 1000’s to coat. Spread a little buttercream over each semicircle and press into the 100’s & 1000’s to coat.
Spoon raspberry jam into the hole in the top of each cupcake. Arrange the semicircles of cake in the jam to create the butterfly wings.
Pipe the buttercream down the centre of each cupcake between the wings.