24 ounces fresh or frozen, thawed cranberries (about 5 cups)
1 1/2 cups packed light brown sugar
1/2 cup ruby or tawny port
Finely grated zest of 1 orange
Kosher salt
SLOW COOKER METHOD
Put the cranberries into a 5- to 8-quart slow cooker. Scoop out about 3/4 cup of the berries and finely chop. Set aside. Stir the sugar, port and half the orange zest into the slow cooker. Season with a generous pinch of salt. Cover and cook on high for 1 hour and 30 minutes.
Stir the cranberry sauce well and set the lid back on the slow cooker so there is a 1- to 2-inch gap, to allow for evaporation. Cook on high for another 1 1/2 to 2 hours, stirring at least twice, taking care around the edges, until many of the berries have popped and the sauce has thickened and is syrupy. Stir in the reserved chopped cranberries and the remaining orange zest. Spoon the cranberry sauce into a serving bowl, cover, and chill in the refrigerator until ready to serve.
STOVETOP METHOD
Put the cranberries into a medium saucepan. Scoop out about 3/4 cup of the berries and finely chop. Set aside. Add the sugar, port and half the orange zest into the pan, and stir. Season with a generous pinch of salt. Bring the mixture to a simmer over medium heat and cook, stirring often, until many of the berries have popped and the sauce has thickened and is jammy and syrupy, 10 to 15 minutes. Stir in the reserved chopped cranberries and the remaining orange zest. Spoon into a serving bowl, cover, and chill in the refrigerator until ready to serve.