Preheat the oven to 180C / 350F / 160C fan forced. Line a muffin tin with paper cupcake liners.
Make the peach puree - destone and roughly chop the peaches then puree in a blender until smooth. Push the puree through a strainer and discard any solids.
In a large bowl, sift together the plain flour and corn flour. Add the sugar, baking powder, ginger and salt and stir well so everything is evenly distributed
Beat the eggs well, until they become frothy (you can do this by hand, or with a hand beater or in a stand mixer). Make a well in the centre of the dry ingredients and add the eggs, butter, milk, and vanilla, and fold to combine (a few very small lumps is fine). Add the peach puree and fold through until almost completely combined leaving just a few thin swirls.
Fill the cupcake liners to about 3⁄4 full, then bake for 22-24 minutes or until a toothpick inserted comes out with just a few crumbs on it. Make sure to turn the tray halfway through cooking so they all cook evenly.
Remove from the oven and allow to cool in the tins for 5-10 minutes before transferring the cupcakes to a wire rack.
FOR THE RASPBERRY PUREE
Use a blender to purée the raspberries, water, sugar and cornflour. Transfer to a saucepan and cook over low heat. Stirring constantly until so thick the spoon leaves a trail that takes a few seconds to fill in again. Strain out the seeds if you prefer then store in the fridge until ready.
Once the cupcakes and the raspberry filling are cool, cut holes out of the centre of each cupcake about 2cm x 2cm. You can use a cupcake corer or just a knife. Now transfer the raspberry filling to a piping bag (or plastic ziplock bag) and cut just the tip off. Fill the hole of each cupcake with the filling, then trim a small piece of the cupcake holes to place back on top to seal it like a plug. Make sure to keep about 2 1/2 tablespoons of the raspberry filling for the following steps.
FOR THE BUTTERCREAM
In a stand mixer with a paddle attachment, beat the butter with 1 tablespoon of the sugar for 5-6 minutes on medium. It needs to be very pale and soft when done. Scrape down the sides half way through then continue beating.
With the mixer on low, add the sugar 1/4 cup at a time until combined. Scrape down the sides of the bowl. Add the salt, vanilla and cream and beat for 5 minutes at medium speed until it looks even lighter, thick and whipped.
Transfer a third of the buttercream to another bowl and whisk in 2 tablespoons of the remaining raspberry filling just until combined (if you overmix, the buttercream could split so just until combined).
Lay out a sheet of plastic wrap on a flat surface and spoon the white buttercream in a thick line about 5x25cm (2.5x10 inches). Spoon the raspberry buttercream right alongside it in a thinner line but the same length. Finally pipe a thin line of the raspberry filling alongside that. Roll the plastic wrap up gently, pulling it together so there is no air bubbles, then slot the whole thing down into a prepared piping bag with tip already in place. Now simply pipe the top of the cupcakes as you normally would.
FOR THE STEWED PEACHES
Place the peaches, water, sugar and cinnamon in a small saucepan over low heat. Cook, stirring, just until the peaches have softened and the sugar is dissolved. Let it cool before topping the cupcakes.
I use a standard Australian 20ml tablespoon (= 4 teaspoons worldwide)
For best results, you should always weigh ingredients like flour and sugar. Kitchen scales are relatively cheap but if you can’t weigh the ingredients, use the spoon and level method (don’t scoop).
I use cornstarch a lot in my baking. Cake flour is a combination of all-purpose and corn starch but in Australia is not so readily available. I use this combo in my recipes a lot instead of using cake flour.
TOOLS USED IN THIS RECIPE
I use these silicone muffin trays for all my cupcakes
A medium ice cream scoop is very handy for portioning out the batter
Either a stand mixer or handheld beater will work great
A cupcake corer is great for cutting a hole in the middle but a sharp knife works too