Heat oil in a 10-inch nonstick skillet over medium heat. Add shallot; cook, stirring, until translucent, 3 to 5 minutes. Add mushroom caps; cook until tender, 8 to 10 minutes.
Add 3/4 cup water and green beans; season with salt and pepper. Stir to combine; reduce heat to low. Cover; cook until beans are crisp-tender, 7 to 10 minutes. If any liquid remains, raise heat, and cook until it evaporates.
This is delicious! Love the mushrooms with the green beans. However neighter my husband or myself cook with salt or pepper. or very little. At our table you would find the pepper mill at my side and the salt shaker at his side and that makes us both happy. thanks for the recipe Martha