• First, trim the green beans with a pair of kitchen shears or a sharp knife.

Cook the Green Beans

• Bring a large pot of water to a boil over high heat. Season with a generous pinch of salt.
• When the water is boiling, gently lower the green beans in the water. Boil them until crisp tender, around 6-10 minutes, depending on your stovetop. (Keep an eye on them because we do not want mushy green beans!)
• Drain the steamed green beans in a colander and set aside for later.

Make the Topping

• While the beans are cooking, slice the onion for the topping thinly.
• Toss in a large bowl with the panko bread crumbs and ½ teaspoon of salt, and set aside.

Make the Mushroom Sauce

• Chop and measure out all the ingredients for the sauce, and place them near your stovetop. You can use the food processor to speed up this process.
• Using the same large pot that the green beans cooked in, heat the olive oil over medium-high heat.
• Add the chopped onion, mushrooms and garlic to the pan. Season generously with salt and pepper, and cook until the onion is translucent, about 6-8 minutes, depending on your stovetop. Continually stir this, as you don't want your veggies to stick to the bottom of the pan.
• Remove the vegetables from the pan and set aside.
• Place the pot back on the stovetop on medium and add the flour. Stir over the heat until it has combined with the leftover fat in the bottom of the pan to create a roux. This is going to thicken our sauce.
• When the roux has been made, add the broth, ¼ cup of almond milk and the seasonings for the mushroom sauce. Simmer lightly.
• When the mixture begins thickening, pour the rest of the non-dairy milk into the sauce.
• Stir until it has thickened, then add back in the mushroom/onion/garlic mix. (Now is the point to taste your mushroom sauce. Feel free to add any additional seasonings, as this'll be the last time you season it!)
• Remove the mushroom sauce from the heat.
• Put together and bake the casserole
• Preheat the oven to 350°F. Spray a baking dish with nonstick baking spray, and set aside.
• Toss the green beans in the mushroom sauce, still in the pan, and stir until the beans are coated.
• Pour into the prepared baking dish. Sprinkle the topping on top of the casserole.
• Place in the preheated oven, and bake for 30-35 minutes, or until bubbly, brown and delicious.
• Enjoy warm!