Heat your oven to 180°C/Fan 160°C/Gas 4. Make sure your butter is out of the fridge and slightly soft. Peel and grate or crush the garlic. Finely chop the parsley leaves.
Put half the pot of butter, the garlic and parsley in a small bowl. Season with a little salt and pepper. Beat together with a fork. Loosely shape into two flattish logs.
Slice a pocket into each chicken breast by pushing the knife in at the thick end and slicing halfway down the chicken. Don’t slice all the way through. Pop the butter inside the pockets.
Lightly press the chicken breasts back together. Sprinkle 1 tbsp of the cornflour on a plate. Season. Pop the breadcrumbs on another plate. Beat the egg in a shallow bowl or plate.
Dip the chicken in the cornflour, then the egg and then the breadcrumbs. Place on a baking tray brushed with ½ tbsp olive oil. Pop in the freezer for 10 mins. Fill a pan with hot water. Bring to the boil.
Scrub and peel the potatoes. Slice them into small cubes about 1 cm big. Add the potatoes to the water. Simmer for 5 mins. Drain. Refill the pan and bring to the boil again.
Bake the Kievs for 30 mins till golden and cooked through. Warm 2 tbsp olive oil in a large frying pan. Add the potatoes and fry over a medium heat for 8-10 mins till golden. Put on a plate lined with kitchen paper.
While the potatoes fry, trim the broccoli and carrots. Peel and slice the carrots into rounds. Simmer them both in the pan for 5 mins. Drain. Serve with the Kievs and potatoes.