Fresh String Bean Casserole

Heat the oven. Preheat to 375°F. Lightly butter or spray a 9x13-inch baking dish.

Blanch the green beans. Bring a large pot of water to a boil. Salt it well (about 1 to 2 tablespoons kosher salt for a big pot). Add the green beans and cook 2 to 3 minutes, until bright green and barely tender. They should still feel firm. Drain, then rinse under cold water to stop the cooking. Shake them dry.

Sauté the mushrooms. In a large skillet over medium-high heat, melt 2 tablespoons butter. Add mushrooms and cook 6 to 8 minutes, stirring occasionally, until they release their liquid and start to brown.

Add onion and garlic. Add the chopped onion and cook 3 to 4 minutes until softened. Add garlic and cook 30 seconds until fragrant.

Make the sauce. Reduce heat to medium. Add the remaining 1 tablespoon butter. Once melted, sprinkle in the flour and stir constantly for 1 minute to cook off the raw flour taste. Slowly whisk in the broth, then the milk. Bring to a gentle simmer, then reduce to medium-low and simmer 4 to 6 minutes, whisking often, until thick enough to coat a spoon.

Finish the creamy base. Take the skillet off the heat and stir in sour cream, salt, pepper, soy sauce (if using), cayenne (if using), and lemon juice. Taste and adjust. You want it a little punchy because the beans will mellow it out.

Combine. Add the blanched green beans to the skillet and toss to coat. Stir in 1/2 cup of the crispy fried onions.

Bake. Pour into the prepared baking dish. Bake uncovered for 20 minutes, until bubbling around the edges and the center is hot.

Add the crunchy top. Sprinkle the remaining 1 cup crispy fried onions on top. Bake 10 to 15 minutes more, until the onions are golden and the casserole is hot and bubbly.

Rest, then serve. Let sit for 5 to 10 minutes so the sauce sets up. Scoop generously and go for the crispy edges first.