Preheat the oven to 375℉.
Arrange the bacon strips onto a sheet pan and place in the oven. Bake for 10 minutes. The bacon should be starting to cook through, but it needs to remain pliable so it can be wrapped around the green bean bundles.
While the bacon is in the oven, blanch your green bean bundles. Bring a pot of water to a boil. Add the beans to the pot and cook for 1 minute, keeping the beans vibrantly green. Cool the beans quickly under cold water. Lay on a paper towel and pat dry.
In a large bowl, combine the beans with the olive oil, rosemary, and garlic salt. Toss well.
Divide the green beans into 4 servings. Take one slice of bacon and create a bundle of beans, ensuring they're evenly bundled. Wrap the bacon tightly around the beans to hold them together.
Arrange the beans on your sheet pan and sprinkle with the brown sugar.
Place the beans in the oven for 15-20 minutes, or until they are tender and the bacon is fully cooked.