Start this recipe by preparing muffins trays with red paper muffin cups. Beat the butter substitute, sugar and vanilla together in a bowl until pale and fluffy. Add the eggs one at a time, beating after each addition (if the mixture looks curdled add a spoonful of the flour.) Mix the yogurt with the food colouring – it should look very, very red since the mixture will fade once cooked. Beat the yogurt into the cake mixture. Fold in the remaining flour and cocoa powder, followed by the milk until well combined. Spoon the mixture into the cupcake paper cases and bake at 200`c for 20-25 minutes, or until well risen and golden-brown and a skewer inserted into the middle comes out clean. When the cakes are ready, remove them from the oven and allow to cool completely. Meanwhile, you can prepare the vanilla frosting. Place the cream cheese, mascarpone cheese and vanilla essence in a bowl and beat together lightly with an electric whisk until smooth. Add in the icing sugar and continue to beat till the mixture is smooth. In another bowl, whip the cream to stiff peaks and gently fold into the cream cheese and yogurt frosting. You should end up with a light, smooth vanilla frosting. Place the frosting in a piping bag fitted with a star nozzle and generously pipe on top of each cupcake. Finally, decorate with fresh strawberries and chocolate hearts.