Preparation
Add green beans to a large pot of boiling water, cover and return to boil. Cook, uncovered, until tender, 6-9 minutes, drain.
Meanwhile, heat 1/1/2 tsp oil in a large nonstick skillet over mediuml-high heat. Add mushrooms and shallots, stirring occasionally, just until tender, about 6 minutes. Add garlic, thyme and salt; cook, stirring constantly, until fragrant, about 1 minute. Stir in the drained beans; heat through.
To make topping, heat the remaining 1/2 tsp oil in a small nonstick skillet over medium heat. Add croutons and onions, cook, stirring and shaking the skillet occasionally, until lightly toasted 1-2 minutes. Romove from heat.
Transfer beans to a a large bowl;sprinkle with topping.