Peel the outer skin off the grapefruit with a knife. Insert the knife along the thin inner part of the skin and remove the fruit from the segments. Tear the fruit into bite-size pieces.

Squeeze the juice from the remaining thin skin and add the salt and pepper. Mix well and then gradually mix in the extra virgin olive oil little by little.

Wash the watercress and tear into smaller pieces, using only the tender stems and leaves. Put the stems and leaves on a plate and place the grapefruit on top.

Pour the dressing from Step 2 on top and serve.