One at a time, place the veal medallions between 2 sheets of plastic wrap and pound with the flat side of a meat mallet until 1/8-inch thick. Season the veal on both sides with 1 teaspoon each of the salt and pepper. Place the flour in a shallow dish. One at a time, dredge the veal medallions in the flour, and shake to remove any excess.
Heat 3 tablespoons of the oil in a large skillet over medium-high heat. Add 3 or 4 of the medallions and cook until golden, about 1 minute per side. Remove from the pan. Cook the remaining medallions, adding more oil as needed.
Discard any oil remaining in the pan, and melt 2 tablespoons of the butter over medium-high heat. Add the mushrooms and green onions and cook, stirring, until wilted, 3 to 5 minutes. Add the crabmeat and the remaining 1/4 teaspoon salt and 1/8 teaspoon pepper. Cook, stirring gently, until warmed through, about 1 minute.
Meanwhile, in a large skillet, melt the remaining 1 teaspoon butter over medium-high heat. Add the asparagus and toss until heated through, about 1 minute.
To serve, shingle 3 medallions alternately with the crabmeat mixture on each of 4 plates. Top each serving with 4 asparagus spears and drizzle with the hollandaise sauce. Serve immediately.
Yield: 4 servings