Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: see manufacturer). Line a baking tray with baking paper. Roughly chop and mix the chocolate and cherries. Rinse orange hot, dab dry and finely grate the peel.
Mix with buttermilk and vanilla extract. Mix 200 g flour, starch, sugar, baking powder, baking soda and salt in a large bowl.
Add cold butter to the flour mixture. Rub in coarse crumbs with your fingertips. Do this quickly! Stir in the buttermilk mix briefly. Then add the chocolate-cherry mixture. Stir only until just enough to form a dough.
Pour the dough onto a lightly floured work surface. The dough is relatively dry - this is correct. With a dough roller or your hands, roll out or beat out the dough to a thickness of approx. 1 1⁄2 cm. Use a heart cutter (approx. 9 cm Ø) to cut out hearts close together, jerking the cutter slightly back and forth.
Put your heart on the plate.
Bake in a hot oven for about 15 minutes until the biscuits have slightly coloured. Take them out and let them cool down on a cake rack.