2 cloves garlic, peeled and finely chopped
2 leeks, washed, halved lengthways and sliced
1 medium onion, peeled and finely chopped
1 tbsp fresh flatleaf parsley, finely chopped
2 sprigs thyme
150g/5oz risotto rice, such as Arborio
450ml/戮 pint hot vegetable stock
75g/3oz unsalted butter
50g/2oz mascarpone
50g/2oz parmesan