Wash the grapes and remove them from the stems. Peel them and carefully remove the seeds from each grape. Place the grapes in a bowl with the white wine and Port. Cover with plastic wrap and refrigerate.
The day of serving
Preheat the oven to 350ºF . Carefully clean the foie gras, removing any small veins, green bits, blood and fat. Wipe quickly and pat dry with a towel.
Peel and wash the carrots and slice into thin rounds.
Place the vegetables and goose fat into a heavy "cocotte" (Dutch oven). Lay the foie gras on top. Cover everything with a sheet of parchment paper. Put the lid on the cocotte and place in the oven for 15 to 20 minutes.