Green Beans with White Wine and Mustard Sauce

This recipe is from The Grit Restaurant Cookbook.

2 tablespoons olive oil
1 teaspoon unsalted butter
1/2 to 2/3 pound fresh green beans, tipped and trimmed
1/4 cup dry white wine
2 teaspoons maple syrup
1/4 teaspoon cider vinegar
1/2 teaspoon Dijon mustard
1/8 teaspoon salt

1. Place olive oil and butter in skillet over medium high heat. When the butter is fully melted, add the green beans and saute, covered but stirring often, until bright green and softened slightly
2. Add the white wine and cover, simmering for 30 to 40 seconds. Add the remaining ingredients and continue to cook. Tossing until the sauce begins to thicken. Beans should be a dark green and tender, but still slightly firm.
3. Serve immediately