Place duck fat in a skillet, and cook over medium to high heat for 4 to 5 minutes, until the fat has melted and some of it has browned.
Add the shallots, and cook for about 30 seconds, stirring occasionally. Add the liver, herbes de Provence, and garlic, and cook over medium to high heat for 1 1/2 to 2 minutes, stirring occasionally. Add the salt and pepper.
Transfer the mixture to a blender, add the brandy (Cognac is most popular), and blend until liquefied. Recipe yields about 1/2 cup. Let cool for at least 1 1/2 hours, then cover and refrigerate until serving time.
Serve the pâté on crackers, toasted baguette slices, or use as sandwich spread. The pâté will keep, well covered, for 3 to 4 days.