Steps
1. Preheat oven to 175°C (350°F) and lightly grease a small heart-shaped cake pan.
2. In a bowl, sift together flour, cocoa powder, and baking powder.
3. In another bowl, whisk egg and sugar until combined, then add milk and melted butter.
4. Gradually fold dry ingredients into wet mixture until smooth.
5. Pour batter into the heart-shaped pan and bake for 15-18 minutes or until a toothpick comes out clean.
6. Let cake cool completely, then prepare frosting by mixing cream cheese, powdered sugar, and pistachio paste until smooth.
7. Spread frosting evenly over the cooled cake.
8. Decorate the edges with chopped pistachios and place mixed fresh berries on top.
9. Using a piping bag or a small spoon, write 'Happy Mother's Day' with melted chocolate glaze on the cake surface.
10. Chill for 30 minutes before serving to let frosting set.