Caramelized Onion-Potato Gratin

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   ["Preheat oven to 375 degrees.", "Combine first 4 ingredients in a small bowl.", "Melt butter in a Dutch oven over medium-high heat; add onions, and cook, stirring often, 15 minutes or until onions are caramel colored; add garlic, and cook 1 minute.", "Stir in flour, and cook, stirring constantly, 1 minute.", "Gradually whisk in milk and next 3 ingredients.", "Cook, whisking often, 8-9 minutes or until mixture thickens.", "Remove from heat; stir in cheese until melted and smooth.", "Layer half of potatoes in a lightly greased 13X9"" baking dish; pour 2 cups of sauce over potatoes in dish.", "Repeat layers once.", "Bake, uncovered, for 1 hour and 10 minutes, or until golden brown and potatoes are fork tender, topping with breadcrumbs during last 15 minutes of baking.", "Remove from oven and allow to stand for 10 minutes before serving."]

* Per serving · 4 servings · Values may vary.