In a skillet over medium-heat. Add diced bacon and yellow onion and cook until crispy, about 4-5 minutes, or until desired crispiness. During the last minute of cooking add minced garlic.

Turn down to medium-low heat. Add the Worcestershire sauce, balsamic vinegar, soy sauce, brown sugar, black pepper, and red pepper flakes (if using). Stir until the brown sugar is melted.

Add in drained green beans. Stir gently to coat in the sauce. Add 2-4 teaspoons of the green bean liquid, if desired.

Cover and cook for about 20 minutes, gently stirring half way through.

Taste and add salt if desired.

Serve warm.