Step 1

Blanch green beans (see notes):Bring a large pot of water to a boil. Add 1 teaspoon of salt and the green beans and cook for 2 minutes. Drain and place in a bowl with ice cold water.

Step 2

Sauté:Heat the oil in a large skillet over medium heat. Add the onion and garlic and cook until softened. Add the beans, season with salt and pepper and sauté until softened to your taste, about 5 minutes.

Step 3

Season:Stir in the butter mustard and lemon juice (if using). Check for seasoning and serve warm.