Homemade Green Bean Casserole (From Scratch Recipe)
This homemade green bean casserole is made completely from scratch with fresh green beans, creamy mushroom sauce, and crispy onions. No canned soup, no shortcuts—just pure, rich, fresh flavor. It’s the upgraded classic that will steal the show on your Thanksgiving table!
Equipment
- Large pot for blanching
- Large skillet
- 9×13-inch baking dish
- Mixing bowls
- Whisk
- Baking sheets (for onions)
Ingredients
- 1½ lb fresh green beans (haricots verts or regular), trimmed and halved
- 2 Tbsp extra-virgin olive oil
- 16 oz cremini mushrooms (or white button), sliced
- 2 Tbsp tamari or soy sauce
- 4 cloves garlic, minced
- 2 Tbsp fresh thyme leaves
- 1/4 cup all-purpose flour
- 3 cups milk (whole, 2%, oat, or almond)
- 1½ tsp Dijon mustard
- 1/2 cup grated Parmesan cheese, plus more for topping
- 1/4 tsp freshly ground black pepper
- 1½ cups French fried onions (store-bought or homemade)
- 2 medium yellow onions, thinly sliced (for homemade topping, optional)
- 1/2 cup all-purpose flour (for coating onions)
- 1 cup panko breadcrumbs
- 2 Tbsp olive oil (for onions)
- 1/2 tsp salt
Instructions
- Preheat oven to 375°F. Toss sliced onions with flour, panko, olive oil, and salt. Spread evenly on two baking sheets and bake for 20–25 minutes, rotating pans halfway through, until golden and crisp. Watch carefully—they brown quickly!
- Preheat oven to 400°F and lightly grease a 9x13-inch baking dish. Bring a large pot of salted water to a boil. Add green beans and blanch for 4 minutes until bright green and crisp-tender. Transfer to ice water to stop cooking, then drain and pat dry thoroughly.
- Heat olive oil in a large skillet over medium heat. Add mushrooms and cook for 8–10 minutes until softened and golden. Stir in tamari, garlic, and thyme. Sprinkle flour over the mushrooms and stir to coat evenly.
- Gradually whisk in milk and Dijon mustard. Simmer 15–20 minutes, stirring often, until thick and creamy. Stir in Parmesan and black pepper. Taste and adjust seasoning.
- Spread one-third of the sauce in the bottom of the prepared dish. Add blanched green beans, then pour remaining sauce evenly over top. Sprinkle with fried onions and a little extra Parmesan if desired.
- Cover with foil and bake 10 minutes. Remove foil and bake another 10 minutes until bubbly and golden. If onions brown too fast, cover loosely with foil. Serve hot.
Notes
Pro Tips: Pat green beans completely dry before adding to the casserole to prevent excess liquid. Let the sauce simmer long enough to thicken fully. Rotate pans when baking homemade onions for even crisping.