Cut the beef in slices approximately 5mm wide and lay a few between two large sheets of baking paper. Beat out each slice paper-thin (about 1mm) with a rolling pin. Gently peel each slice from the paper and lay the slices over one large plate, or as four single servings.
Scatter the olives over the beef followed by the walnuts. Finely grate over the zest of the lemon half. Squeeze over the lemon juice, then splash over the oils before scattering generously with flaked sea salt and the dried chile flakes. Follow with a little black pepper and a scattering of the marjoram.