Preheat the oven to 170°C and lightly grease a large baking dish.
Toast the almonds for 5-10 minutes and chop 1/3 of the nuts and set them aside.
Cream together the butter and sugar until well blended.
Whisk together the eggs, orange rind, liqueur, baking powder and salt.
Stir in 570 ml of the flour along with the polenta, toasted almonds and coriander seeds (if used).
Place the dough on a clean surface and knead until smooth.
Work in the remaining flour a little at a time until you have a soft dough (it shouldn't be sticky).
Divide the dough into 4 equal pieces and shape each into a flattened roll about 5 cm wide and 2-3 cm high.
Place the rolls on the prepared baking sheet, sprinkle with chopped almonds and bake the rolls until the edges begin to brown, about 20-25 minutes.
Leave to cool for 10 minutes then cut the rolls into 1 cm slices widthways.
Place the slices on the baking sheet and bake until pale brown.
Chocolate cups: Slowly heat the cream without letting it come to the boil.
Break the chocolate into squares and stir them into the hot cream a few at a time until completely
Remove from heat and stir in the egg yolks and brandy.
Spoon the mixture into espresso cups.
Chill in the fridge and serve with the biscotti.