1. First, make the streusel topping. Sift the flour and salt into a large shallow bowl.
2. Toss in the butter and rub in with your fingertips until it resembles large breadcrumbs. A few lumps are ok.
3. Stir in the sugar and toasted hazelnuts and pop in the fridge until you are ready to use it.
4. Preheat the oven to 190°C/375°F/gas 5 and line a muffin tin with 12 paper muffin cases.
5. In a bowl sift together the flour, bicarbonate of soda, salt, ginger and green cardamom seeds.
6. In a large bowl mix together the butter, sugar, eggs, milk and vanilla essence.
7. Fold the flour into the wet mixture, only using 15-20 strokes.
8. Stir in the chocolate chips, toasted hazelnuts and raisins (if using), being careful not to over-mix or your muffins will be dense.
9. Quickly fill the muffin cases to the top.
10. Sprinkle over the streusel topping and bake in the centre of the oven for 20 minutes, or until they are well-risen and golden brown. Test by inserting a skewer down the centre, it should come out clean.
11. Leave to cool on a wire rack.