Preheat your oven to 375°F (190°C).
In a saucepan, heat the olive oil over medium heat. Add the chopped onion and cook until translucent, about 5 minutes. Add the minced garlic and cook for another minute.
Stir in the almond milk, vegetable broth, nutritional yeast, salt, and pepper. Bring to a simmer and cook for a few minutes until slightly thickened.
Layer half of the sliced potatoes in a greased baking dish. Pour half of the sauce over the potatoes. Repeat with the remaining potatoes and sauce.
Cover the baking dish with foil and bake for 30 minutes. Remove the foil and bake for an additional 30 minutes, or until the potatoes are tender and the top is golden brown.
Let it cool for a few minutes before serving.