FRESH GREEN BEAN CASSEROLE

Method:

1. For the Topping: Combine Panko, salt and pepper in a small bowl and set aside. In a large skillet over medium-high heat, saute onions in 2 tablespoons of unsalted butter for about 10 minutes. Reduce heat to medium-low and sprinkle with salt and cook, stirring occasionally, for about 30 minutes, or until the onions are golden, caramelized and soft. Combine onions with panko mixture and set aside.
2. For the Beans and Sauce: Adjust oven rack to middle position and heat oven to 425 degrees.
3. Fill a large bowl with ice water. Bring 4 quarts of water to a boil in a large pot or Dutch oven. Add 2 tablespoons salt and beans. Cook beans until bright green and crisp-tender, about 6 minutes. Drain beans in colander and plunge immediately into ice water to stop cooking. Spread beans on paper towel-lined baking sheet to drain.
4. Add butter to now-empty pot and melt over medium-high heat until foaming subsides. Add mushrooms, garlic, 3/4 teaspoon salt, and 1/8 teaspoon pepper; cook until mushrooms release moisture and liquid evaporates, about 6 minutes.
5. Add flour and cook for 1 minute, stirring constantly. Stir in broth and bring to simmer, stirring constantly. Add cream, reduce heat to medium, and simmer until sauce is thickened and reduced to 3 cups, about 10 minutes. Season with salt and pepper to taste.
6. Add green beans to sauce and stir until evenly coated. Arrange in an even layer in 3-quart (or 9x13-inch) baking dish. Spread onion mixture over the top. Bake until top is golden brown and sauce is bubbling around edges, about 15 minutes. Serve immediately.