Line 2 baking sheets with nonstick baking paper. Place the butter and sugar in a large bowl and beat together using a hand-held electric whisk until light and fluffy. Add the egg and orange extract, if using, and beat well. Stir in the cranberries and raisins, then sift in the flour and bicarbonate of soda and mix to form a stiff mixture.
Place 8–10 mounds of the mixture, well spaced apart and without flattening, on the prepared baking sheets.
Bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 12–15 minutes, or until pale golden. Leave to cool on the sheets for 2–3 minutes, then transfer to wire racks to cool completely.