In a nonstick, melt butter. Stir in onions and liver and cook for 1 minute over medium-high heat. Pour in wine and let boil. Place lid over skillet, lower heat, and simmer for 2 minutes. Take skillet off of heat and reserve.
In a food processor or blender, pulse liver mixture, duck meat, sour cream, thyme, salt, allspice, and pepper until there are no lumps; scrape down the sides of the bowl.
Place mixture in a serving bowl, wrap in plastic wrap and put in refrigerator for at least 1 hour. Scatter pistachios over pate before serving.