Pre – heat the oven to 200°C, 400°F, Gas Mark 6.
Combine the Parsley, Mint, Rosemary, lemon juice, breadcrumbs, cheese and 1 tbs of the oil in a bowl.
In a large pan, heat remaining oil and brown lamb on all sides and season generously. Transfer to a roasting dish, brush the fat side of the racks with the mustard, then pack on the herb crust. Arrange the racks in the roasting dish so that their bones are interlinked.
Roast in the oven for 20-25 minutes, depending on required doneness.