Wash and prepare the aubergines/eggplants, cut in half and then lengthways into ½-cm/⅛-inch thin slices. Lay out pairs of slices which fit together in terms of size. Arrange on a work surface. Season well with salt and pepper.
Cut the cheese into very thin slices and arrange on one half of the aubergines/eggplants. Wash the tomatoes, remove the stalks, cut in half and then into 3-mm/⅜-inch slices and arrange on top of the cheese. Pluck the thyme leaves and sprinkle on top of the tomato slices. Cover with the remaining aubergine/eggplant slices.
Stir the cornflour/cornstarch with 4-5 tablespoons water; put the breadcrumbs in a deep plate. Carefully roll the prepared aubergine/eggplant cordon bleus first in the cornflour/cornstarch, then in the breadcrumbs and press these on. Fix with a tooth pick, if needed.
Heat plenty of oil in a frying pan and fry the aubergines/eggplants on both sides for a few minutes until golden brown. Lay on the baking tray lined with baking paper and bake in the pre-heated oven at 180°C/355°F/gas mark 4 for 7-12 minutes.
Tips: Serve the cordon bleus on a tomato coulis or with vegan herb butter. Cordon bleus can be prepared and fried in advance; finish off in the oven before serving. The ‘no-moo’ cheese which can be bought in wholefood shops is excellent for cordon bleus.