Combine the sugar, cornstarch, and water in a medium-sized saucepan over medium heat and stir to combine. Heat until the mixture is wet and the sugar begins to melt.

Add the raspberries and stir to coat with the sugar mixture. Continue to cook until the raspberries start to soften and let out juices. Use your spatula to mash the raspberries.

Continue to cook until raspberry mixture has thickened, about 5-7 minutes. You don’t need to boil the mixture to thicken it, but if it does begin to boil, don’t boil for more than 1 minute. Keep in mind that the mixture will thicken as it cools.

Remove raspberry mixture from heat and strain to remove the seeds, if desired. Pour the mixture into another bowl and refrigerate until completely cool.

Prepare a cupcake pan with cupcake liners. Preheat oven to 350°F (176°C).

Combine the flour, cocoa powder, baking soda, and salt in a medium-sized bowl and set aside.

Add the melted butter, vegetable oil, sugar, and vanilla extract to a large bowl and mix until well combined.

Add the egg and mix until well combined, then add the milk and mix until well combined.

Add the dry ingredients to the wet ingredients and mix just until well combined. Don’t over mix.

Add the hot water and mix until well combined.

Divide the cupcake batter between the cupcake liners, filling a little more than halfway full (50g). Bake 14-17 minutes, or until a toothpick inserted into the center comes out clean.

When the cupcakes have cooled, make the buttercream. Add the butter to a large mixer bowl and beat until smooth.

Add about half of the powdered sugar and beat until well combined and smooth. If you intend to frost the cupcakes as in the photos, you’ll want to use the larger amount of powdered sugar so that you have enough buttercream.

Add 4 tablespoons of raspberry filling and the vanilla extract and beat until well combined and smooth.

Add the remaining powdered sugar and beat until well combined and smooth. Add the additional raspberry filling, as needed, to get the right flavor and consistency of frosting.

When the cupcakes have cooled, use a cupcake corer to remove the centers from the cupcakes.

Fill each cupcake with one tablespoon of raspberry filling, then pipe the buttercream on top of the cupcakes.

If using the chocolate ganache, drizzle it over the raspberry buttercream. You can use a squeeze bottle or add it to a piping bag fitted with a Wilton 10 tip to have a little more control.

Add a raspberry on top and any other toppings you might like.

Serve immediately or store in the fridge in an air-tight container. Best served at room temperature, since the buttercream will get quite firm when cold. Best if eaten within 4-5 days.