Bring all ingredients to room temperature. Also for the pistachio cream.
Preheat oven to 180°C top/bottom heat.
Coarsely chop chocolate and cut butter into pieces.
Melt chocolate and butter in a bowl over a water bath and let cool briefly.
Mix flour with baking powder cardamom, cinnamon and salt.
Beat eggs with sugar and vanilla extract until foamy.
Slowly add chocolate-butter mixture to egg-sugar mixture.
Fold flour mixture into chocolate mixture and gradually add milk.
Grease muffin tray or line with paper bags.
Pour batter into the cups of the muffin tin and bake in the oven for about 20 minutes.
Then allow to cool completely.
Pistachio cream
Beat softened butter in a bowl with a hand mixer on high speed until pale, about 5 minutes.
Sift in the powdered sugar and add the pistachio paste. Stir everything together.
Finally, add the cream cheese and stir the cream briefly until smooth.
Put the pistachio cream in a piping bag with a star-shaped nozzle and pipe it onto the cooled chocolate muffins. If your pistachio cream is too liquid, put it in the refrigerator for a few minutes. There it can cool down, becomes firmer in consistency and is easier to spread on the muffins.
Garnish chocolate muffins with pistachio cream as desired and serve.