David Elliot Rock Cornish Hens small size means they cook faster than a whole chicken, and their skin crisps up delightfully in the oven. in this recipe the Cornish hens are made with a punchy, flavorful harissa and herb dressing. A little lemon brightens it all up, and the hens bake on a sheet tray, with crispy smashed potatoes. It’s dinner in less than an hour – the best kind of dinner.