- 1 yellow onionthinly sliced
- 1 red onionthinly sliced
- 2 1/2cups buttermilk(see DIY below)
- 1 1/2cups all-purpose flour
- 1cup panko breadcrumbs
- 1/2tsp EACH salt and pepper
- vegetable or canola oil for frying
- 1 3/4pounds (28 oz) green beanstrimmed and cut in half
- 3tablespoons unsalted butter
- 2tablespoons olive oil
- 12oz. cremini mushroomssliced ¼” thick
- 4 garlic clovesminced
- 1teaspoon salt
- 1/4cup all-purpose flour
- 3cups low sodium chicken broth
- 1/2cup heavy cream
- 1 1/2teaspoons Dijon mustard
- 1 1/2teaspoons Worcestershire sauce
- 1tsp EACH dried thyme, dried parsley
- 1/2teaspoon pepper
- 1/4tsp EACH dried oregano, nutmeg
- 1/2cup freshly grated cheddar cheese
- 1/4cup freshly grated Parmesan cheese
- 1/2cup sour cream
Add onions to a shallow baking dish and pour buttermilk over top. Press the onions down so they’re submerged as much as possible. Let them soak at room temperature for an hour, stirring and pushing down occasionally. Cover and refrigerate if soaking longer.
When ready to fry onions, fill a Dutch oven or deep heavy duty pot with approximately 2 inches of oil. Heat to 375 degrees F.
While heating, combine flour, panko, salt and pepper in a large bowl; set aside. Line a large baking sheet with paper towels; set aside.
Test the oil with a small pinch of panko; if it bubbles and fries, then it is hot enough. Using tongs, transfer a handful of onions from the buttermilk to the flour/panko mixture. Toss to combine, shake off any excess flour, then carefully transfer to the hot oil.
Fry onions until lightly golden brown (just 1-2 minutes), watch closely! – they will continue to darken when baked. Remove fried onions with a heat-proof slotted spoon or tongs to paper towels. Repeat with the remaining onion slices.
Bring a large pot of water to a boil and stir in two tablespoon salt. Add the green beans and blanch 5 minutes (start timing as soon as you add the beans). Meanwhile, prepare a large bowl of ice water to transfer the greens to. Using a slotted spoon, transfer beans to ice water to stop cooking. Drain the beans and set aside.
Melt 3 tablespoons butter with 2 tablespoons olive oil over medium heat in a Dutch oven or large pot. Add mushrooms and cook until nicely browned and starting to soften, 3-5 minutes. Season with 1 teaspoon salt and add garlic; sauté 30 seconds.
Whisk in flour then cook, while stirring for 1 minute. Turn heat to low then gradually whisk in chicken broth and heavy cream followed by Dijon, Worcestershire sauce and all spices/seasonings.
Bring sauce to a boil, whisking constantly then reduce heat to a simmer, whisking often until thickened, about 6-8 minutes.
Remove skillet from heat and whisk in cheddar until melted followed by Parmesan cheese until melted. Whisk in sour cream until blended.
Pat green beans dry then add to sauce; stir to combine. Stir in 1 ½ cups fried onions. Stir in additional broth if needed to thin.
Transfer green beans to a lightly greased 9×13 baking dish. Top with desired amount of onions. Bake at 350 degrees F for 15-20 minutes or until hot and bubbly.