Step 1

Fill up a large bowl of water and a few handfuls of ice, set aside.

Step 2

Bring a large pot of water to a rolling boil. Add a heavy pinch of salt, the green beans, and the bell peppers. Stir to dissolve the salt and cook the vegetables until bright and still crisp, just a few minutes. With a sieve or slotted spoon, remove the vegetables to the bowl of ice water to stop them from over cooking. Once the vegetables are cooled remove them to a paper towel-lined baking sheet and pat dry.

Step 3

To prepare the mushrooms: In a small saucepot on medium heat add 2 cups of water, the vinegar, mushrooms, garlic, thyme, and 1 teaspoon salt. Stir to dissolve the salt, cover and cook on medium heat for 15 minutes. Turn off the heat and let it rest covered for 15 minutes more.

Step 4

To make the vinaigrette: Whisk together the mustard, 4 tablespoons of the liquid the mushrooms are soaking in, and olive oil in a small bowl. Season with some salt and a grind or two of pepper.

Step 5

Shake the excess liquid off the mushrooms and add them to a large bowl along with the cooked vegetables and the vinaigrette. Toss and serve with fried onions sprinkled over the top.