Mix all the cream heart ingredients (mascarpone, cream, vanilla, icing sugar) together by whipping gently (not overmuch as mascarpone easily turns to butter).
Dampen the cheese cloth and line your dish with it, pressing the cloth into the corners of the heart.
Scoop the mixture into the cheese cloth lined dish and smooth the top. Give the mould a little bang on the worktop. Place on a saucer in the fridge to drain for a few hours.