
Preheat the oven to 350.
Start by boiling the diced potatoes until almost fully cooked. Drain and set to the side.
Use a small blender to make the sauce. Combine all sauce ingredients and blend until smooth. Set to the side for later use.
Meanwhile in a medium skillet sauté the onion and garlic in olive oil. When the onions are almost done add in the collard greens. Stir and season with salt and pepper.
Lightly grease a baking dish. Add the potatoes. Top the potatoes with the sautéed greens and onions. Pour the blended sauce over the top of the casserole. Use a spoon to even things out and mix in baking dish as needed.
Bake for 50 minutes to one hour. The casserole will not be set firm but most liquid will have evaporated into thickened sauce.