Roughly chop two-thirds of the sorrel, set aside the remainder for garnish. Using the whisk on a hand mixer, beat the eggs and sugar in a bowl until the mixture becomes lighter in colour. Mix in the butter, milk and chopped sorrel. Mix in the flour, almonds, salt and baking powder. Transfer the mixture to the prepared muffin tin.
Approx. 20 mins. in the centre of an oven preheated to 180°C. Remove from the oven, allow to cool slightly, remove from the tin, leave to cool.
Thoroughly mix the cream cheese and icing sugar. Transfer the mixture to a piping bag with a serrated nozzle (approx. 10 mm in diameter) and pipe onto the muffins, garnish with the reserved sorrel.