Preheat oven to 375 F.
In a skillet over medium-low heat, add 3 Tbsp avocado oil and allow it to simmer.
Add sliced onions and garlic.
Saute until caramelized, about 30-35 minutes. Stir as needed.
In a steam basket inside a pot, steam the green beans until tender, about 5-6 minutes.
Drain and set aside.
In a mixing bowl, add gluten-free breadcrumbs and 1 Tbsp avocado oil.
In a 3-quart casserole dish, lightly oil the bottom and add 1/2 the caramelized onions.
Add green beans over onions.
Pour mushroom soup over beans.
Spread remaining caramelized onions over sauce.
Sprinkle bread crumbs and sliced almonds over surface.
Cover and bake for 30-35 minutes.
Sauce should be bubbling.
Uncover and place dish under broiler to brown breadcrumbs and almonds for 3-5 minutes.