1. In a deep, heavy-bottomed saucepan, stir together the green and red grapes, sugar, lemon juice and mustard seeds. Cook over medium-high heat until the grapes burst and the juices begin to gel, about 1½ hours.

2. Remove the pan from the heat and set aside to cool to room temperature, about 20 minutes. Stir in the pecans, tarragon, marjoram, bourbon and Dijon mustard and season with salt and pepper.

3. Let the mostarda rest for at least half an hour before serving. Store in a covered container in the refrigerator for up to one month.