Melt the chocolate in a bowl over simmering water. Let it cool.
Preheat the oven to 170°C.
Add the sugar and eggs to the cool chocolate, stir to combine. Stir in the bicarbonate of soda & salt, then the orange zest and liqueur (if used) or juice.
Add the ground almond & flour (if used) and stir to combine. Fold in the cranberries.
Tip the mixture into a lined baking tin (about 20x20 cm) and spread out evenly.
Bake for 20 to 25 minutes. Don’t overbake - the middle of the cake should be gooey i.e. not cooked through entirely.
Let it cool in the tin then slice into squares.