A flattie is a South African speciality, i.e. a spatchcock chicken so-called because it's laid out flat. At this South African restaurant the bird has been brined for 24 hours, coated in a herby/spicy rub and then slow-grilled on an open fire, aka the braai.
The flattie is offered as a South African alternative to the traditional British roast, and it's dished up family-style with all the trimmings, i.e with pork stuffing, spiced broccoli, and butternut squash.