Step 1Place a shallow flameproof casserole (preferably earthenware), or an enameled cast-iron pan over low heat, add the ramps with the butter, cover with a sheet of crumbled wet parchment and cook gently until the ramps soften, 5 to 10 minutes.
Step 2Lift off the parchment, add three-fourths teaspoon salt and one-fourth teaspoon pepper, the asparagus, cream and ham; gently toss, cover with the same parchment paper and a lid and cook for 5 to 10 more minutes, or until the asparagus and ramps are tender. Add one-half teaspoon of the black truffle oil; stir to combine.
Step 3Remove the asparagus, ramps and ham from the pan with a slotted spoon. Divide among 8 plates. Cook the cream and cooking juices to thicken and reduce to about 2 tablespoons, about 2 minutes.
Step 4Make a light vinaigrette by whisking together the vinegar, salt and pepper, walnut oil and the remaining one-half teaspoon truffle oil. Add the reduced cream-cooking juice to the vinaigrette.
Step 5In a mixing bowl, toss half the vinaigrette with the baby greens. Dribble the remaining vinaigrette over the ramps and asparagus.
Step 6Divide the salad evenly among the 8 plates. Garnish each serving with a sprig or two of sunflower sprouts and serve.