Green Bean Casserole with Onions
This slow cooker version of the beloved green bean casserole blends the simplicity of convenient ingredients with the richness of a homemade mushroom sauce—all while leaving the oven free for other dishes. A classic addition to any holiday table, this comforting side is finished with a crispy onion topping for added texture and flavor.
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Servings: 10
Ingredients
- 3 cups of pre-packaged crispy fried onions reserved for topping
- 1 ½ cups of full-fat heavy cream
- 2 frozen 12-ounce bags of cut green beans not thawed
- 1 pound of white button mushrooms cleaned, stems trimmed, and sliced
- 1 ½ cups of chicken stock preferably low-sodium
- 3 tablespoons of plain all-purpose flour
- ¾ teaspoon of salt plus additional for seasoning
- ⅛ teaspoon of freshly cracked black pepper or to taste
- 3 medium-sized garlic cloves finely minced
- 3 tablespoons of unsalted butter
Instructions
- In a large skillet or Dutch oven, melt the butter over medium-high heat until it begins to foam. Add in the prepared mushrooms, minced garlic, ¾ teaspoon salt, and ⅛ teaspoon black pepper. Sauté for approximately 5 to 7 minutes, or until the mushrooms release their liquid and become tender.
- Sprinkle the flour evenly over the mushroom mixture. Stir constantly for 1 minute to eliminate any raw flour taste. Gradually whisk in the chicken broth, ensuring to scrape up any caramelized bits from the bottom of the pan. Bring to a boil, whisking continuously.
- Lower the heat to medium and pour in the heavy cream. Simmer the mixture for around 5 minutes, or until the sauce thickens to a creamy consistency. Taste and adjust seasoning with extra salt and pepper if needed.
- While the sauce simmers, microwave the frozen green beans according to the instructions on the packaging. Alternatively, cook them on HIGH for 4 to 5 minutes, then let rest for 1 minute. Drain thoroughly; using a salad spinner is recommended to remove excess moisture.
- Once drained, fold the warm green beans into the mushroom cream sauce, ensuring every piece is evenly coated. Transfer the mixture into the insert of a slow cooker.
- Cover and cook on HIGH for 2 hours or on LOW for 4 hours, or until the internal temperature at the center reaches 165°F.
- Immediately before serving, scatter the fried onions generously across the surface of the casserole.
Notes
Mushroom substitution: For best results, use fresh mushrooms to create a quick, rich cream-based sauce from scratch.
Green bean alternative: If using fresh beans, trim and chop 2 pounds. Blanch in 4 quarts of boiling salted water for 5 minutes, then transfer immediately to an ice water bath to stop cooking. Drain thoroughly.
Onion topping substitution: For a homemade breadcrumb topping, pulse 4 slices of sturdy white bread in a food processor until coarse crumbs form (about 3 cups). Mix with 3 tablespoons of melted butter or olive oil, then sauté over medium-high heat until golden and crisp. Use in place of canned fried onions.
Yield: Makes approximately 10 cups of casserole, suitable for 10 side portions. May serve more if part of a larger meal spread.
Storage: Refrigerate any leftovers in an airtight container for up to 4 days.
Make-ahead option: The mushroom cream sauce can be prepared up to 2 days ahead and stored chilled. When using pre-made cold sauce, extend slow cooker time to 3 hours on HIGH or 5 hours on LOW.