In a wide-bottomed saucepan, add ½ tablespoon of coconut oil and set to low heat. Add the onions and cook for 30 minutes. Stir occasionally to caramelize. If the onions look dry, splash a bit of water into the pan.
Put the parsnips in a steamer for about 10 minutes. Set aside and let them cool.
Remove the ends of the green beans and cut them into 2-inch (5 cm) pieces. Steam them for 8 minutes. Set them aside in an 8×8-inch (200×200 mm) baking dish.
Once the onions have caramelized, set them aside. Sauté the mushrooms in the same pan for one minute.
Add garlic, and stir for 5 minutes.
Add half of the garlic and mushroom mixture to the green beans.