1. Preheat the oven to 350F.
2. In a pot over medium-high heat, add 2 cups of soy milk, the sliced mushrooms, garlic, and black pepper. Slowly bring to a boil and reduce the heat to a simmer. Dissolve the cornstarch into the remaining 1/2 of soy milk and add to the pot. Stir well for 5 minutes and remove from the heat.
3. Drain the beans and pour them into a casserole dish. Add about 1 cup of the French-fried onions to the beans, as well as the soy milk mixture and toss. Place in the oven for 35-45 minutes, top with the rest of the French-fried onions, then cook for a few more minutes until the onions are brown.
4. Let the casserole sit for 10-15 minutes to set and cool.

2 1/2 cups plain soy milk
1 1/2 cups sliced mushrooms
4 (14 ounce) cans cut green beans
1 1/2 tablespoons cornstarch
15 ounces French-fried onions
1-2 teaspoon garlic powder
Fresh ground pepper, to taste