Preheat your oven to 180°C.
Add cider vinegar to soy milk in a jug, whisk briefly until combined and set aside for a few minutes. The milk should thicken slightly.
Sift your flour, cocoa, baking powder, bicarb and salt into a separate bowl, add the caster sugar, and stir to combine.
Add sunflower oil and vanilla extract to your soy milk mixture and whisk to combine.
Pour your wet ingredients into your dry ingredients and stir gently until everything is incorporated into a thick, glossy batter.
Divide your cupcake batter between 12 cupcake cases in a muffin tin. You may need to use a jug to pour this mixture as it is very liquid and hard to spoon!
Bake for 15 minutes, or until the cupcakes have risen and are springy to the touch. Allow to cool completely on a wire rack.
For the Dairy-free Chocolate Buttercream:
Begin by beating your margarine and shortening in a freestanding mixer until creamy and soft. Add the cocoa powder and vanilla and beat into a dark paste.
Add your icing sugar gradually, ensuring that each addition is incorporated before added the next. You may need to scrape down your bowl a few times to make sure this is all combined.
If you find that your buttercream is heavy, add a tablespoon or two of soy milk.
Allow a good 5 minutes of beating, once all ingredients are combined, to create a wonderfully fluffy dairy-free buttercream.
For the decoration:
Begin by piling a teaspoon of chocolate buttercream on the top of each cupcake.
Roll out your white sugarpaste to approximately 5mm thickness (you can use marzipan spacers to help with this) and cut out 12 circles with your 5cm cutter.
Lay each circle of icing on top of your cupcakes, above the mound of chocolate buttercream. Press very gently around the edges of your icing to encase the buttercream underneath the icing. If you go gently, you should find that no buttercream escapes.
Cup your hand and twist it gently over the top of your covered cupcake to create a perfectly smooth rounded top.
Roll out your red sugarpaste to approximately 3mm thickness and cut 12 small hearts. You can make these hearts glittery by brushing the tops lightly with water and sprinkling edible red glitter over them.
Attach your hearts to the cupcakes with a small dab of water. Press them down gently and they should stick.
If you want to add a scroll to your hearts, roll out a little white sugarpaste to 3mm thick and trim into thin strips of around 5mm width.
Cut out scroll shapes using the pointed end of your heart cutter. These should be around the same length as your heart shape and the cutter is a great guide for this.
Attach a scroll to your heart using a small dab of water and write your message using either a black paste colour and paintbrush or an edible ink pen.
Charlotte White is a professional cake designer based in London. Her company, Restoration Cake, has a reputation for creating stunning bespoke celebration cakes that taste as good as they look. Charlotte’s first book, Burlesque Baking, is available for pre-order now!