3 large carrots (around 550g/1录lb), peeled and cut into 2cm/戮in pieces
6 garlic cloves
2 kohlrabi (around 650g/1lb 7oz), trimmed, peeled and cut into 2cm/戮in cubes
3 leeks, trimmed and cut into 2cm/戮in lengths
2 sprigs fresh thyme
1 bay leaf
salt and freshly ground black pepper
40驳/1陆辞锄 butter