In a small pot combine the wine, shallots, garlic, peppercorn, and basil stems. Add the lemon to the pot, squeezing the juice in first. Bring to a simmer over medium-low heat and reduce to 1/4 cup. Add the cream to the pan and reduce it to half. Strain the sauce and season with salt and pepper. Keep over low heat until ready to serve. When ready to serve add the chopped basil. Spoon a thin layer of sauce on the plate. Top with gnudi, and the fish. Serve immediately.