Ingredients
Scale
For the Roasted Garlic:
- 2 whole heads of garlic
- 2 tablespoons olive oil
- Salt and pepper to taste
For the Casserole:
- 2 pounds fresh green beans, trimmed
- 3 tablespoons butter
- 1 pound cremini or button mushrooms, sliced
- 1 medium yellow onion, diced
- 3 cloves garlic, minced (in addition to roasted)
- 3 tablespoons all-purpose flour
- 2 cups whole milk
- 1 cup chicken or vegetable broth
- 1 cup sour cream
- 1½ cups shredded gruyère or sharp cheddar cheese
- 1 teaspoon fresh thyme leaves
- Salt and pepper to taste
For the Topping:
- 1½ cups panko breadcrumbs
- 3 tablespoons melted butter
- ½ cup grated parmesan cheese
- ½ teaspoon garlic powder
Instructions
- Preheat your oven to 400°F. Cut the top ¼ inch off each garlic head to expose the cloves.
- Place them on a piece of foil, drizzle with olive oil, and season with salt and pepper. Wrap the foil around them tightly.
- Roast for 40-45 minutes until the cloves are golden and soft. Let them cool, then squeeze the roasted cloves out of their skins and mash them into a paste.
- Bring a large pot of salted water to a boil. Add the green beans and cook for 4-5 minutes until bright green and crisp-tender.
- Drain and immediately plunge them into a bowl of ice water to stop the cooking. Drain again and set aside.
- In a large skillet or Dutch oven, melt the butter over medium-high heat. Add the mushrooms and cook for 6-8 minutes until they’ve released their liquid and are starting to brown.
- Add the diced onion and cook for another 3-4 minutes until softened. Stir in the minced garlic and cook for 30 seconds.
- Sprinkle the flour over the vegetables and stir constantly for about 1 minute. Gradually whisk in the milk and broth, stirring constantly to prevent lumps.
- Bring to a simmer and cook for 3-4 minutes until the sauce thickens. Remove from heat and stir in the mashed roasted garlic, sour cream, shredded cheese, and thyme.
- Season generously with salt and pepper. Fold in the blanched green beans until everything is well coated.
- Transfer the mixture to a 9×13-inch baking dish. In a small bowl, combine the panko, melted butter, parmesan, and garlic powder.
- Sprinkle the breadcrumb mixture evenly over the casserole. Bake at 375°F for 25-30 minutes until the top is golden brown and the sauce is bubbling around the edges.
- Prep Time: 25 minutes
- Cook Time: 1 hour 15 minutes
