Place the leaves of 1 baby cos lettuce, 8 pieces thinly sliced toasted baguette, broken into pieces, and 6 slices grilled prosciutto, broken into pieces, in a bowl and set aside.
Place 2 tablespoons lemon juice, 1/2 cup whole-egg mayonnaise, 1 clove crushed garlic, 1/4 cup finely grated parmesan cheese, salt and pepper in a bowl and stir to combine.
Add to the lettuce and toss gently to combine. Top with shaved parmesan to serve.