Make the Raspberry Coulis
1-Place the frozen raspberries and sugar in: Place the frozen raspberries and sugar in a tall saucepan and heat on medium heat until they are softened and reach a boil. Reduce the mixture until thick bubbles are bursting on top. (See notes if using fresh raspberries.)
2-Transfer to a blender or food processor: Transfer to a blender or food processor and blitz until a smooth puree is formed.
3-Pass the mixture through a sieve to: Pass the mixture through a sieve to remove any excess seeds.
4-Let cool completely before using: Let cool completely before using. The consistency should be kind of similar to ketchup.

Make the Raspberry Cupcakes
5-Preheat oven to 350°F / 180°C and: Preheat oven to 350°F / 180°C and line a cupcake pan with cupcake liners.
6-Cream butter and sugar together until pale: Cream butter and sugar together until pale and fluffy.
7-Add egg and stir until combined: Add egg and stir until combined.
8-Combine flour, baking powder, baking soda and: Combine flour, baking powder, baking soda and salt in a bowl. Add half of the flour mixture to the batter and mix in completely.
9-Add the milk, vanilla and ½ cup: Add the milk, vanilla and ½ cup of the prepared and cooled raspberry puree. Keep the rest of the puree for the filling and frosting later.
10-Mix in the milk and raspberry completely,: Mix in the milk and raspberry completely, then add the remaining flour and stir in. It should be a beautiful pink colour.
11-Scoop cupcake batter into cupcake liners and: Scoop cupcake batter into cupcake liners and bake for 17 minutes or until the tops of the cupcakes spring back when you press them lightly.
12-Let the cupcakes sit for a few: Let the cupcakes sit for a few minutes after removing from the oven, then transfer to a wire rack to cool completely.
13-Once cooled, use a cupcake corer or: Once cooled, use a cupcake corer or a spoon to scoop out a hole in the centre of each cupcake and fill with 1 teaspoon of raspberry coulis.

Make the Raspberry Russian Buttercream
14-Make sure your butter is at the: Make sure your butter is at the right temperature, not too hot and not too cold. For best results, remove your butter from the fridge one hour before making the frosting.
15-Using a stand mixer, whip the butter: Using a stand mixer, whip the butter on high for five minutes, scraping down the sides of the bowl regularly.
16-Slowly incorporate the condensed milk, whipping in: Slowly incorporate the condensed milk, whipping in between additions.
17-Add ½ cup of the prepared raspberry: Add ½ cup of the prepared raspberry coulis and whip until combined.
18-Whip for a further minute to allow: Whip for a further minute to allow the frosting to thicken up. It should be beautifully glossy and thick enough to pipe. If it isn’t, see notes.
19-Decorate the cupcakes with the buttercream and: Decorate the cupcakes with the buttercream and fresh raspberries.