As the nation’s favourite home cook, Mary Berry (right) has a reputation to uphold. So before a dish can grace the pages of her books – which numbered 74 at the last count – she tries it out on her most discerning critics.

The author and TV cook, known to millions as a judge on The Great British Bake Off, enlisted the help of her five grandchildren for her latest cookbook and BBC2 series, Mary Berry Cooks, in which she shares her favourite meals for family and friends.

In the show, the youngsters – who range in age from three to 11 – help their grandmother, who turned 79 last month, make treats for a tea party and enjoy a Sunday lunch she has prepared.

MEDITERRANEAN ALL-IN-ONE CHICKEN (Serves 6)

Ingredients

1kg main crop potatoes (such as King Edward or Maris Piper), peeled and cut into 5cm chunks

3tbsp olive oil

1 large onion, cut into wedges

2 garlic cloves, crushed

6 rashers of smoked streaky bacon, snipped into 1cm pieces

6 chicken thighs

6 chicken drumsticks

5 preserved lemons, cut into quarters (or one sliced lemon)

1.5tsp paprika

3 courgettes, thickly sliced

1 x 200g can anchovy-stuffed green olives, drained (or plain green or black ones)

Salt and freshly ground black pepper

Method

Preheat the oven to 220C/200C fan/Gas 7.

Place the potatoes in a large roasting tin with two tablespoons of the oil. Toss well to coat them.

Add the onion, garlic, bacon and chicken pieces and toss together.

Add the lemons to the roasting tin. Season everything well and sprinkle with the paprika. Roast for 40 minutes.

In a bowl, toss the courgettes in the remaining tablespoon of oil and season with salt and pepper, then poke them in among the chicken and scatter the olives over the top. (Don’t overcrowd the roasting tin. You need everything in a single layer or it will not cook evenly – divide between two tins if necessary.)

Return to the oven for a further 20 minutes, until the chicken and vegetables are golden brown and tender.