Cut the chicken fillets into 3cm strips and place in a bowl with the plain flour. Toss together until completely coated.
In another bowl, place the beaten egg and, in a third bowl, place the breadcrumbs, lemon zest and parmesan, and toss together well.
One by one, dust the flour from the chicken pieces and then dip in the egg. Allow any excess egg to drip back into the bowl, then toss the pieces in the breadcrumb mixture until evenly coated. Set aside on a large plate and cover with greaseproof paper while you repeat with the remaining chicken pieces.
For the mash, place the potatoes in a saucepan of cold water and bring to the boil. Simmer for 3 mins then add the sweet potato and cook for a further 8 mins. Drain well and return to the saucepan. Add the fromage frais and mash well.
Meanwhile, heat the oil in a large frying pan and cook the chicken for about 3 mins each side until golden and cooked through. Serve with fresh cooked peas for toddlers. Place a few cooked chicken strips with some mash and extra fromage frais in a blender, and purée, chop or mash according to your baby’s needs.