You will need blue Creative Kitchen or Dollar Sweets cupcake cases, mini water balloons and vegetable shortening for this recipe.
Begin the edible lightbulbs the day before to allow time to set.
110g butter, softened, plus extra for greasing
150g caster sugar
3 large (60g) eggs
175g plain flour
1/4 tsp bicarbonate of soda
125ml low-fat natural yoghurt
2 tsp vanilla extract
Blue gel food colouring
6 tbsp gelatine powder
12 tbsp water
12 x twist marshmallows
500g white fondant
Yellow and concrete/grey gel food colouring
Blow up mini water balloons to about the size of a golf ball and secure with a knot. Lightly grease the balloons with vegetable shortening, wiping off any excess with paper towel.
In a small saucepan combine gelatine and water, stir to mix then allow to sit for 3 mins.
Place over a medium heat and cook, stirring, until the gelatine has dissolved completely. Colour with yellow gel food colouring, then allow to cool slightly.
One balloon at a time, dip a balloon into the gelatine mixture, swirling to coat.
Poke the bottom tie of the balloon into a baking rack (use plastic bag clips or pegs to secure underneath).
Repeat with 11 more balloons then set aside the cooling rack (somewhere draught-free) for 8 hours or until the gelatine sets very firm and dry.
Use small, sharp scissors to pierce the balloons from the bottom tie, then carefully pull the balloons out of the gelatine shell (if the shell compacts in, it can be gently pushed out from the inside).
Knead fondant until soft and pliable. Colour with concrete/grey gel food colouring and knead until colour is incorporated.
Roll the fondant out to about 5mm thick. Use a small, sharp knife to cut rectangles to wrap around 12 of the twist marshmallows. Secure with a tiny bit of water.
Preheat the oven to 180ºC (160ºC fan). Place 12 of the cupcake cases into a 12-hole muffin tin.
In a large bowl, mix the butter and sugar together with an electric beater until pale and creamy.
Add the eggs, one at a time, whisking each one in with a tablespoon of the flour. Carefully fold in the remaining flour using a large metal spoon, then fold in the yoghurt and vanilla extract until well combined.
Divide mixture between cupcake cases and smooth over so surface is flat.
Bake 25-30 mins until lightly golden and centres spring back when gently pressed. Remove from oven and allow cupcakes to cool in tin for 15 mins before transferring to a wire rack to cool completely.
To decorate, colour buttercream with blue gel food colouring.
Pipe a flat rosette onto the cooled cupcakes.
Top each cupcake with the marshmallow lightbulb base, pipe a little buttercream on top of the marshmallow to help secure the “bulb” then carefully place a gelatine bulb on top (you can use small, sharp scissors to cut a hole in the base of the gelatine bulbs so they sit flat on top).