Prepare Green Beans - Wash the green beans thoroughly under cool water and drain well. Trim off the string ends. If the beans are very long, cut them in half. Set aside.
Cook the Mushrooms - In a large skillet, heat the olive oil over medium heat. Add the mushrooms and ½ teaspoon salt. Saute until tender and lightly brown, 2 to 3 minutes.
Cook the Aromatics - Add the garlic, and cook until fragrant, 30 seconds. Add the onions, and saute until translucent, 1 to 2 minutes.
Cook Green Beans - Add the green beans, water, soy sauce, ½ teaspoon salt, and pepper to the pan. Stir to combine. Increase to medium-high heat. Cover and cook until the beans are tender and bright green, about 3 to 4 minutes. If still crisp, add ¼ cup water and steam until crisp-tender. Remove the lid and stir until the water evaporates, about 1 minute.
Add the Butter - Turn off the heat and add the butter. Stir until melted and combined.
To Serve - Taste and season with more salt and pepper as desired. Serve while still hot.
Notes
Recipe Yield: About 4 cups
Serving Size: About 1 cup
Storing: Cool and store in an airtight container in the refrigerator for up to 5 days.
Reheating: Cover and cook in the microwave in 30-second increments until hot. On the stovetop, cook over medium heat until hot.
Using Frozen Beans:Do not cover. Simmer in water until defrosted and hot, about 5 to 7 minutes.
Using Canned Beans:Use 4 cups of drained canned beans. Skip the steaming step. Add to mushroom mixture with butter, and stir until beans are hot, about 3 to 5 minutes.
Blanching the Beans: If you prefer to blanch the beans in salted, boiling water instead of steaming, cook until tender, about 3 to 5 minutes. Add directly to the mushroom mixture.
Make it Vegan:Substitute butter with olive oil.
Make it Whole30, Paleo, & Gluten-Free:Usegheeinstead of butter. Use coconut aminos instead of soy sauce.