Boil or steam potatoes until tender (about 20 minutes). Pour in almond milk, and mash until smooth. Put corn in a food processor and process about 10 seconds to break corn into smaller pieces. Mix corn with potatoes, and add parsley, salt, and pepper.
Preheat oven to 350º F. Heat olive oil over medium heat, and cook onions until soft and translucent. Add green onions and garlic, and cook one minute, stirring constantly so garlic doesn't burn.
Stir into potato-corn mixture. Lightly spray or rub a 9 x 13-inch casserole dish with olive oil, and spread mixture into dish. In a small bowl, use a fork to mix corn flour, olive oil, and garlic powder until well blended. Sprinkle over top of casserole, and bake 30 minutes.
Yield: 12 servings (serving size: about 1/2 cup)