Green Bean and Bacon Casserole

2 pounds fresh green beans, trimmed and cut into 1-inch pieces (or 4 cans of green beans, drained)
8 slices of bacon, chopped
1 medium onion, finely chopped
2 cloves garlic, minced
1 can (10.5 oz) cream of mushroom soup
1/2 cup sour cream
1/2 cup milk
1 cup shredded cheddar cheese (optional)
Salt and pepper to taste

Prepare the Green Beans:
- If using fresh green beans, bring a large pot of salted water to a boil. Add the green beans and cook for about 5 minutes until tender-crisp. Drain and set aside.
Cook the Bacon:
- In a large skillet, cook the chopped bacon over medium heat until crispy. Remove the bacon with a slotted spoon and place on a paper towel-lined plate to drain. Reserve 2 tablespoons of the bacon grease in the skillet.
Cook the Onions and Garlic:
- In the same skillet with the reserved bacon grease, add the chopped onion and cook until softened, about 5 minutes. Add the minced garlic and cook for another 1-2 minutes until fragrant.
Prepare the Sauce:
- In a large bowl, mix together the cream of mushroom soup, sour cream, milk, and half of the shredded cheddar cheese (if using). Stir in the cooked onions and garlic. Season with salt and pepper to taste.
Assemble the Casserole:
- Preheat your oven to 350°F (175°C). Grease a 9×13 inch baking dish.
- Add the cooked green beans to the baking dish. Pour the sauce mixture over the green beans and stir to combine.
- Sprinkle the crispy bacon pieces evenly over the top of the casserole. If using, sprinkle the remaining cheddar cheese over the top.
Bake:
- Bake in the preheated oven for 25-30 minutes, or until the casserole is hot and bubbly, and the cheese is melted and golden.
Serve:
- Remove from the oven and let it cool slightly before serving.