1. For the greens:

   Wash each leaf and strip them from their center stems. Discard the stems and coarsely chop the leaves into large pieces. Mix them together.
2. Pour the oil into a large sauté pan set over medium heat. When hot and add just enough greens, with the water still clinging to the leaves, to fill the pan. Cover the pan and wilt the greens for a minute or 2. Add the rest of the greens and a pinch of salt. Cover the pan and cook for 10 to 15 minutes, or until greens are wilted and tender.
3. Let the greens cool briefly, then squeeze the greens dry with your hands. Set aside.

For the vinaigrette:

1. In a mortar, mash the garlic to a paste with pestle, sprinkling in a little salt as you pound.
2. When the garlic is an absolute paste, mash in the vinegar with the pestle and beat in the oil with a fork. Taste and add salt and pepper, if needed.

To serve:

1. With tongs, toss the greens in a bowl with enough vinaigrette to coat evenly. Form into a loose mound on a platter.
2. Arrange slices of proscuitto around the circumference of the greens. Garnish with mustard blossoms if you can possibly find them. Serve warm or at room temperature.