Add the green beans to a large pot of boiling salted water and cook for 3 minutes.
Strain the beans and keep them in the draining basket. No need to run them under cold water or shock them in ice water. It’s best to let them slightly air dry.
While the beans are drying out, add the oil to a large 12” frying pan over medium-high heat until it begins to smoke lightly.
Place in the beans and sauté for 1 to 2 minutes or until they become lightly browned.
Turn the heat down to medium-low and push the beans to one side of the pan in the other add in the garlic and butter and stir and cook for 30 to 45 seconds or until it becomes fragrant.
Mix the green beans with the garlic and butter and remove the pan from the heat.
In a small bowl, mix together the mustard and soy sauce.
Add the mustard-soy mixture to the pan of beans along with lemon juice, salt, and pepper.
Mix until combined.
Serve with optional red pepper flakes.
