Spiced biscotti with an orange syllabub dip

Name: Spiced biscotti with an orange syllabub dip
Ingredients: 350g/12oz plain flour, plus extra for dusting; 2 tsp baking powder; 2 tsp mixed spice; 250g/9oz golden caster sugar; 1 orange, zest only; 85g/3oz raisins or currants; 85g/3oz goji berries or dried cranberries; 50g/1¾oz cashews or macadamias, roughly chopped; 50g/1¾oz pecans or pistachios, roughly chopped; 3 large free-range eggs, beaten; 50g/1¾oz caster sugar; 300ml/10fl oz whipping cream; 2 oranges, zest and a little juice; 4 tbsp whole milk