Instructions

Prepare the crunchy onion topping:

1. Preheat the oven to 475 degrees.
2. Combine the flour, bread crumbs, and salt together in a large bowl.
3. Toss onions into the flour mixture.
4. Brush a baking sheet with the cooking oil.
5. Spread the onions evenly out over the baking sheet.
6. Place the sheet pan of onions in the oven and bake.  After about 15 minutes, turn the onions over. Finish baking until done and golden brown approximately 30 minutes.
7. Remove from oven and set aside.

Prepare the casserole:

1. Lower the heat in the oven to 400 degrees F.
2. Bring a large pot of water to a boil.  Add 2 tablespoons of salt.
3. Add the beans and cook/blanch for about 5-6 minutes.
4. Immediately drain, and place the beans in a large water bath (a bowl of ice mixed with cold water).  This allows the beans to stop cooking.
5. Once cool, drain the water off of the beans and set aside.
6. Melt the butter in a large skillet over medium heat.
7. Add the shallots, garlic, mushrooms and salt and pepper.
8. Cook, stirring occasionally, until the mushrooms begin to lose some of their liquid (about 5 minutes).
9. Add 2 tablespoons flour to the mushroom mixture and stir well.
10. Cook for 2-3 minutes.  Add the cream and half-and-half and simmer.  Allow to simmer until the mixture thickens, about 5-10 minutes.
11. Pour beans in a 9" x 12" casserole dish.  Top mixture with the baked onions.
12. Place in oven and bake for about 12 minutes, or until bubbly.
13. Remove from oven and serve.