USA · Vegetable and Mushroom Dishes
Green Bean Casserole from Scratch
Fresh green beans keep a gentle snap under a savory mushroom cream sauce, while crisp onions provide the salty crunch people expect from this American holiday casserole.
Ingredients
- green beans900 g
- cremini mushrooms250 g
- yellow onion1
- garlic3 cloves
- unsalted butter45 g
- all-purpose flour35 g
- whole milk500 ml
- heavy cream120 ml
- soy sauce15 ml
- fresh thyme leaves1 tsp
- fine salt1.5 tsp
- black pepper0.5 tsp
- crispy fried onions120 g
- olive oil20 ml
Method
- 1Blanch the beans. Bring 3 litres of water and 1 teaspoon of the salt to a full boil, add the trimmed beans and cook for 4 minutes. Transfer them straight into ice water for 3 minutes, then drain and dry thoroughly; this fixes the color and prevents carryover cooking.
- 2Brown the mushrooms. Heat olive oil in a wide 30 cm skillet over medium-high heat and add mushrooms in one layer. Cook untouched for 4 minutes, then stir and cook 4 minutes more until their moisture is gone and the edges are brown. Move them to a plate so they do not steam in the sauce.
- 3Cook the aromatics. Reduce the heat to medium, melt butter in the same skillet and add the onion. Cook for 6 minutes until soft and pale gold, then add garlic and thyme for 1 minute. Scrape up the browned mushroom residue because it supplies much of the savory flavor.
- 4Make the cream sauce. Sprinkle flour over the onion and stir for 2 minutes so it loses its raw smell. Add milk in four additions, whisking smooth each time, then add cream, soy sauce, remaining salt and pepper. Simmer for 5 minutes until the sauce coats a spoon but still pours slowly.
- 5Assemble the casserole. Fold the mushrooms and the dried-off beans through the sauce, then transfer everything to a buttered 23×33 cm baking dish. The sauce should cling rather than pool; if the beans released water, leave that water behind. Scatter only 40 g of the fried onions through the surface and reserve the rest.
- 6Bake until bubbling. Heat the oven to 190°C and bake the casserole uncovered for 20 minutes. It is ready for its topping when the sauce bubbles around the edges and the center is hot. Stirring during baking would break the beans and make the sauce look greasy.
- 7Crisp the top and rest. Spread the remaining 80 g fried onions evenly over the casserole and bake for 7 minutes more until deep gold. Rest for 8 minutes before serving so the sauce thickens around the beans. Do not cover during the rest or the trapped steam will soften the topping.