Best Green Bean Casserole

1 medium yellow onion, thinly sliced
1 tablespoon ground flaxseed
2 pinches sea salt
2 pinches black pepper
24 ounces fresh green beans, trimmed and cut into bite-size pieces (8 cups)
1 tablespoon sliced almonds

CHUNKY MUSHROOM GRAVY
1 yellow onion, cut into ½-inch dice (2 cups)
16 ounces mushrooms, sliced (8 cups)
6 cloves garlic, minced
⅓ cup oat flour
2 cups low-sodium vegetable broth
2 tablespoons white wine vinegar
1 tablespoon Italian seasoning
Sea salt and freshly ground black pepper, to taste

Preheat oven to 350°F.
Line a baking sheet with parchment paper.
In a mixing bowl, combine thinly sliced onion, flaxseed, salt, and pepper.
Mix well to coat onions; let sit for 5 minutes.
Spread onions on prepared sheet and bake 15 minutes until lightly brown around the edges.
Set aside.
Meanwhile, place green beans in a steamer basket in a large saucepan.
Add water to just below basket.
Bring to boiling.
Steam, covered, about 10 minutes or until tender.
Remove from heat and transfer beans to a 2½-qt. baking dish.

To make gravy, combine diced onion, mushrooms, and garlic in a saucepan over medium heat.
Cover pan and cook, stirring occasionally, for 7 to 10 minutes or until onions start to turn translucent.
The mushrooms will release enough liquid to keep the vegetables from sticking to the pan.
In a medium bowl, whisk together oat flour, broth, vinegar, and Italian seasoning; season with salt and pepper.
Add broth mixture to mushroom mixture; cook for 3 to 5 minutes more, or until gravy thickens.
Transfer half of gravy to a blender.
Purée until smooth.
Return puréed mixture to saucepan and stir well.
Pour the gravy over the green beans in the casserole dish.
Scatter browned onions and almonds over the top.
Bake about 20 minutes or until heated through.

Makes 8 cups
Note: For less crunchy green beans, steam approximately 15 minutes. I substituted unbleached flour for the oat flour.
A recipe inspired from forksoverknives.com