Wash and snip the end of the Green Beans (1.5 pound). Roughly chop the Onion (1) and mince the Garlic (2 clove). Chop the Portobello Mushroom (2) and set everything aside.
Bring a Water (1 gallon) and Salt (2 tablespoon) to a boil. Add the green beans and blanch for 5 minutes. While the green beans are boiling, prepare a big bowl of water with ice.
After blanching, transfer the green beans to the ice bath to stop the cooking process. Drain the green beans and set aside.
In a large saucepan or skillet over medium high heat, melt your Unsalted Butter (2 tablespoon). Add the chopped onions and minced garlic and stir until the onions soften. About 4 to 5 minutes.
Add the chopped portobello mushrooms, Salt (1 teaspoon) and Ground Black Pepper (1/2 teaspoon). Continue to cook for 1 to 2 minutes.
Sprinkle the all All-Purpose Flour (2 tablespoon) and stir to combine. Cook for 2 minutes.
Add the Chicken Broth (1 cup) and stir to combine.
Add the Half and Half (1 cup) and simmer until the mixture thickens, stirring occasionally, approximately 6 to 8 minutes. Preheat the oven to 375 degrees F (190 degrees C).
In a buttered 9x13 baking dish, transfer the green beans and distribute evenly.
Top with the sauce and mix evenly.
Sprinkle the Breadcrumbs (1/2 cup) on top.
Spread the Fried Onions (6 ounce) on top.
Bake in preheated oven for 20 minutes or until you see the sauce bubble. Serve warm.