1 tbsp. extra-virgin olive oil
4 tbsp. slices of bacon, cut into 1/2" pieces
1/4 c. all-purpose flour
3 c. whole milk
1 tsp. Worcestershire sauce
1 tsp. garlic powder
3 c. shredded cheddar, divided
Kosher salt
Freshly ground black pepper
1 c. French's fried onions
2 tbsp. freshly chopped chives
Preheat oven to 350°. Prepare an ice bath. In a large pot of boiling water, add green beans and cook until bright green, about 6 minutes. With a slotted spoon or tongs, quickly transfer green beans to ice bath to cool, then drain and transfer to a large bowl. In a large, high-sided skillet over medium heat, heat oil. Cook bacon until crisp, 8 minutes. Remove bacon from skillet and drain on a paper towel lined plate. Over medium heat, whisk in flour and cook until lightly golden and no longer raw, about 2 minutes. Add milk, Worcestershire, and garlic powder and bring up to a simmer, stirring occasionally. Let mixture thicken slightly, about 2 minutes, then whisk in 2 1/2 cups cheddar until completely melted. Season with salt and pepper and remove from heat. Combine green beans and cheese sauce in a medium baking dish. Top with remaining cheddar and bake until warmed through and bubbling around the edges, about 20 minutes. Top with bacon and fried onions and bake 5 minutes more. Garnish with chives before serving.