Clean, wash and dry spinach salad. Wash tomatoes, dab dry and cut in half. Peel shallots and cut into fine cubes. Add vinegar, sugar and mustard to the shallots and gradually stir in 3 tablespoons of oil, season with salt and pepper.
Cut toast slices into small cubes. Roast pine nuts in a pan without fat until golden brown, take them out. Heat 2 tablespoons of oil in a pan, roast the toast cubes at medium heat until golden brown and season with 1 pinch of salt.
Drain the croutons on kitchen paper. Wash the chicken fillets, dab dry and season with salt and pepper. Heat 2 tablespoons of oil in a frying pan, fry meat over medium heat while turning for about 10 minutes.
In the meantime, mix lettuce, tomatoes and pine nuts in a bowl. Shortly before the chicken filets are cooked, mix the salad with the vinaigrette and arrange on plates. Remove the meat, cut into thin slices and place on the salad.
Sprinkle croutons over it.