- Spatchcock the poussins: place the poussin on a chopping board, breast-side down, cavity facing you. Using kitchen shears or sharp scissors, cut down each side of the backbone to remove; discard the backbone. Open out the poussin, flip it over (so it’s breast-side up) and flatten it down using the heel of your hand. Repeat with the other poussins. Alternatively, buy the poussins ready-spatchcocked.
- Make the marinade by blending all the ingredients together. Arrange the spatchcocked poussins in a single layer in a large baking dish or tray. Season generously with sea salt and freshly-ground black pepper.
- Using a pastry brush, generously brush the poussins on both sides with the marinade, getting into every nook and cranny. Alternatively, rub the marinade over the poussins by hand. Let sit and marinate at least 30 minutes, or up to 4 hours.
- Heat barbecue to medium-high. Grill the poussins, breast-side down first, until well-browned and slightly charred, 5 minutes; flip the poussins and repeat. Reduce the heat down to medium, close the lid and grill, turning occasionally, until just cooked through, 20 to 25 minutes.
- Transfer the cooked poussin to a platter and allow to rest at least 10 minutes before serving.
- Oven method: arrange the marinated spatchcocked poussins in a single layer on one (or two) large roasting tins. Roast, breast-side up, until well-browned and cooked through, 30 to 35 minutes.