Season the liver well with salt and freshly ground black pepper, then dredge in the seasoned flour, shaking off any excess flour.
Melt the butter in a pan over a medium heat until it foams.
Add the liver to the pan of melted butter and cook for three minutes, until the liver had turned slightly brown, then turn the liver over and cook for another three minutes.
Turn the liver over again, reduce the heat a little, and drizzle the liver with the balsamic vinegar. Cook for a further 2-3 minutes, or until cooked to your liking.
Add the bacon, watercress, rocket, cucumber and sun-blushed tomatoes to the pan and stir well for ten seconds.
To serve, place a piece of liver onto each plate and arrange the pan juices and vegetables around the plate.
