In a large pot or Dutch oven, heat over medium heat and add diced bacon. Sauté for about 5–7 minutes until crispy.

Add finely chopped onion, cook for another 5 minutes until translucent. Add minced garlic, sauté for 30 seconds.

Carefully remove the bacon and onion mixture from the pot, leaving rendered fat.

Add trimmed green beans, pour in enough chicken broth to cover, and sprinkle with Cajun seasoning. Stir to combine.

Bring to a low boil, cover, reduce heat to low and simmer for 1 to 1.5 hours, stirring occasionally.

Drain excess broth and return the reserved bacon and onion mixture to the pot, mixing thoroughly. Heat through for 1–2 minutes.

Stir in butter until melted, adjust seasoning with salt and pepper. Serve warm.