How to Make It
Preheat the oven to 400°. Fold the guinea hen wing tips under the wings. Season the hen cavities with salt and pepper and tuck 4 pieces of lemon inside each one. Tie the legs together with kitchen string. Transfer the hens to a medium roasting pan, breasts up. Rub 1 tablespoon of butter all over each guinea hen and season generously with salt and pepper. Pour the water into the roasting pan, add the garlic and dates and roast for 30 minutes.
Reduce the oven temperature to 350°. Add the Pinot Noir to the roasting pan and roast the hens for about 50 minutes longer, or until the skin is richly browned and crisp and the breasts are just done. Remove the hens from the oven and increase the oven temperature to 400°.
Meanwhile, in a small dry skillet, toast the cumin seeds over moderately high heat until fragrant, about 30 seconds. Transfer the cumin to a mortar and let cool. With a pestle, grind the seeds to a powder. Add the chives, thyme and the remaining 2 tablespoons of butter and stir to blend. Season the cumin butter with salt and pepper.
Discard the strings. Transfer the hens to a carving board. Using a sharp knife, cut the legs off the hens at the thigh joint. Return the legs to the roasting pan, skin side up and roast for 10 minutes longer, or until they are cooked through, then transfer to the carving board.
Set the roasting pan over 2 burners. Add the stock and simmer over moderately high heat, stirring to scrape up any browned bits stuck to the bottom of the pan. Simmer for 1 minute. Strain the juices through a coarse sieve set over a small saucepan. Using a rubber spatula, press the soft garlic and dates through the sieve; scrape the puree from the bottom of the sieve and add to the saucepan. Pour in any accumulated juices from the birds; bring to a simmer, whisking until smooth. Remove from the heat and whisk in the reserved cumin butter and the lemon juice. Season with salt and pepper. Thickly slice the breasts and separate the drumsticks from the thighs. Serve with the sauce.