Beat the butter with the herbs, garlic, lemon juice and a little pepper. Spoon into a line about 25 cm (10 inches) long on a sheet of clingfilm or foil, then roll up into a neat log shape. Freeze for 15 minutes.
Meanwhile, put one of the chicken breasts between two large sheets of clingfilm and beat with a rolling pin until it forms a rectangle about 3 mm (⅛ inch) thick, being careful not to make any holes in the chicken. Repeat with the other chicken breasts.
Cut the herb butter into 4 pieces and put one on each chicken breast. Fold in the sides, then the top and bottom, to make a tight parcel.
Put the flour on a plate and the breadcrumbs on a second plate, and beat the eggs in a shallow dish. Roll the kievs in the flour, then coat in the egg and roll in the breadcrumbs. Put back on to the empty flour plate and chill for 1 hour (longer if you have time).
Heat the oil in a large frying pan, add the kievs and cook over a medium heat for 5 minutes, turning until evenly browned. Transfer to a baking sheet, then complete cooking in a preheated oven, 200°C (400°F), Gas Mark 6, for 15 minutes or until the chicken is cooked through. Serve with new potatoes and braised red cabbage.