Cut the fillet of beef into thin slices with a sharp knife and arrange on a plate.
Carefully wrap the plated fillet of beef slices in foil and keep cold until serving.
Slice the mushrooms and cherry tomatoes and put them to the side.
Make the salad dressing in a separate bowl: Place the balsamic vinegar in a bowl, season with salt and pepper and slowly stir in the olive oil with a whisk. Add 1/2 teaspoon Dijon mustard and whisk again.
Remove the prepared fillet of beef from the foil and arrange on the plates.
Season the carpaccio with salt and pepper, drizzle with a little olive oil and lemon juice.
Combine the lettuce, tomatoes and mushrooms together and mix with the salad dressing. Once the salad is coated well, arrange it in the middle of the carpaccio.