Preheat oven to 350F.

Chop the green beans into bite-sized pieces. Thinly slice the mushrooms and remove any tough stems. Set aside.

In a large pan over medium high heat, add the olive oil to warm up for 1 minute.

Add the chopped green beans and sliced mushrooms. Season with salt to sauté 8-10 minutes, until tender and green beans are a bright green.

Remove the veggies to large, oven-safe casserole dish.

Add the butter to melt in the now empty pan over medium high heat.

Add the garlic to sauté for 30 seconds, then stir in the 2 tablespoons of flour until fully absorbed.

Gradually whisk in one cup of the milk. Mix until smooth and thickened, about 1-2 minutes. Gradually add in ½ cup at a time of the remaining milk and heavy cream, whisking until smooth and thickened, about 3-4 minutes.

Whisk in the remaining tablespoon of milk to help thicken up the sauce even more.

Remove from heat to stir in the seasonings and Worcestershire sauce.

Pour over the sauteed veggies in the casserole dish. Add the grated cheddar and mix until all ingredients are well-combined.

Cover with foil or the casserole lid to bake 30 minutes.

Remove the cover to add the fried onions. Cook 8-10 more minutes, until fried onions are golden on top.

Let rest 10 minutes before enjoying warm!