For the halloumi, heat the oil in a frying pan and fry the halloumi slices for 2-3 minutes on each side, until golden-brown.
For the tomato sauce, heat the oil in a saucepan and cook the tomatoes, sugar and ketchup until thickened. Season, to taste, with salt and freshly ground black pepper.
To serve, place the toasted ciabatta onto a plate, drizzle with olive oil and top with the tomato sauce and halloumi. Garnish with chervil.