Melt the butter in a medium saucepan. Add the barley and cook over high heat for 2 minutes, stirring frequently. Add the scallions and cook for 1 minute, stirring constantly. Add the sun-dried tomatoes, salt and pepper. Stir in the boiling water and return to a boil. Reduce the heat to low, cover and cook, stirring occasionally, until the barley is chewy, 35 to 40 minutes. Serve with the roast veal and the sauteed broccoli rabe.