Shallot-Tarragon Jam

What I'm making this weekend...should be delicious on hot panini sandwiches. This is from Chow:

In this jam, shallot pairs with tarragon to create an instant appetizer spread that’s great on roasted turkey or spooned over a log of fresh goat cheese.

• 2 tablespoons olive oil
• 1 tablespoon unsalted butter
• 1 1/2 pounds shallots, peeled, halved, and sliced 1/4-inch thick
• 1/2 teaspoon kosher salt
• 6 tablespoons white wine–tarragon vinegar
• 1/4 cup granulated sugar
• 2 tablespoons chopped tarragon

1. Heat oil and butter in a medium saucepan over medium heat.
2. When butter foams, add shallots and salt. Cook, stirring occasionally, until shallots are softened and just beginning to brown, about 10 minutes. Season with freshly ground black pepper.
3. Stir in 4 tablespoons of the vinegar and the sugar and cook, stirring occasionally, until the shallots are completely soft and caramelized and the jam is thick and syrupy, about 20 to 25 minutes.
4. Remove from heat and stir in remaining 2 tablespoons vinegar. Allow jam to cool for 20 minutes. Stir in chopped tarragon.