Prepare the Oven and Tin: Preheat the oven to 180°C/160°C fan/350°F and line a 12-hole cupcake tin with cupcake liners.
Make the Cupcake Batter: Place the soft butter, caster sugar, beaten eggs, vanilla extract or bean paste, self-raising flour, and baking powder in a large mixing bowl. Beat everything together until you have a smooth, evenly combined batter.
Fill the Cupcake Cases: Divide the batter between the prepared liners, filling each one approximately two-thirds full.
Bake the Cupcakes: Bake for about 20 minutes, or until the cupcakes have risen, turned golden, and spring back lightly when pressed.
Cool Completely: Remove the baked cupcakes from the tin and transfer them to a wire rack. Leave them to cool completely before filling or decorating.
Prepare the Buttercream: Beat the unsalted butter with half of the sifted icing sugar until smooth and free of lumps. Add the remaining icing sugar, vanilla, and 1–2 tablespoons of milk. Beat on high speed until the buttercream becomes very light and fluffy.
Create the Filling: Using an apple corer or sharp knife, remove a small piece from the center of each cooled cupcake to create a cavity.
Fill with Strawberry Jam: Spoon approximately 150g of strawberry jam into the cupcake centers, dividing it among the 12 cakes.
Pipe the Buttercream: Fit a piping bag with a 1M piping tip and fill it with the prepared vanilla buttercream. Pipe the buttercream generously over each filled cupcake.
Add the Eton Mess Topping: Finish each cupcake with crushed meringue, one fresh strawberry, and a drizzle of ready-made strawberry sauce.
