Cannelloni with Truffle Cream

Name: Cannelloni with Truffle Cream
Ingredients: 1 tbsp. olive oil, plus 1 tsp. for greasing; 5 oz. boneless veal shoulder, cut into 2 pieces; 5 oz. boneless pork shoulder, cut into 2 pieces; 1 small yellow onion peeled and coarsely chopped; 1 clove garlic, peeled and chopped; 2 tbsp. marsala; 2 oz. foie gras, cubed; 2 1⁄2 cups heavy cream; 1 1⁄2 cups chicken stock; 2 tbsp. finely chopped jarred black truffle; 5 tbsp. butter; 1 tbsp. flour; 1 cup milk, hot; 1 pinch freshly ground nutmeg; 18 cannelloni wrappers; 1⁄2 cup freshly grated Parmigiano-Reggiano; Salt and freshly ground black pepper