Potato Leek Casserole (Dairy Free, Gluten Free).

Preheat the oven to 350 degrees F.
Thinly slice the white and light green parts of the leeks and soak them in a few changes of water to remove the dirt. Drain the water out.
Cook the vegan buttery spread in a medium sized pot over medium heat, so that it melts. Add the sliced leeks and cook for about 5 minutes, stirring often, until they are soft and tender.
Stir in the gluten free flour blend or corn starch, then add half of the non-dairy milk and stir well. Add the salt and pepper and the rest of the milk and turn the heat to medium high.
Cook the sauce while stirring constantly for a few minutes until it starts to thicken. Keep stirring so it doesn't burn.
Place the thinly sliced potatoes in a casserole dish. Pour the sauce over the potatoes. Dot the top with two tablespoons of vegan buttery spread.
Cover the casserole dish with foil (or a lid) and bake at 350 degrees F for 30 minutes. Remove the cover and continue to bake for 45 minutes. The top should get nicely browned and the sauce will be bubbling.
While the casserole is in the oven, make the garlic breadcrumbs if you are going to make them from scratch. After the casserole is done baking, put the breadcrumbs on top, and bake for an additional 10 minutes.
Let the casserole stand for about 15 minutes before serving.