To make the marinade, mix the mustard with the oil and spices. Rinse the chicken (inside and out) in cold water, pat dry.
Vegetables and chicken
Coat the chicken with 2/3 of the marinade. Mix the rest with the corn cobs, potatoes and onion. To make the tomato sauce, mix the tomatoes with the chilli and rosemary, season. Spread the sauce onto a baking tray lined with baking paper, place the chicken and garlic on top.
Roast for approx. 30 mins. in the centre of an oven preheated to 200°C. Remove from the oven, add the potatoes and sweetcorn, cook for a further 30 mins., turning the potatoes and corn cobs once.