Instructions

1. Preheat the oven to 375 degrees and lightly grease an 8×12 casserole dish. This will also work in a deep dish pie dish.
2. Slice the potatoes very thinly, about the same thickness of a penny. You can do this with a food processor using the slicing attachment, a mandoline or a sharp knife. I found that a knife was the easiest. Set aside.
3. In a large saucepan over medium heat, heat the butter over medium heat. Once the butter has melted, add in the flour and stir well until the flour has completely dissolved. Cook, stirring frequently for about 2 minutes until the flour mixture is toasted and golden brown.
4. Add in the onion and cook another 2 minutes, stirring frequently to prevent burning.
5. Add in the garlic, dried spices and cook another 30 seconds, then stir in the vegetables, salt and pepper.
6. Add in the water and use it to deglaze the pan by scraping your spoon along the bottom to remove any flour/onion bits. Cook for 5 minutes, stirring frequently until vegetables are cooked down and have released most of their liquid.
7. Reduce heat to low and slowly stir in the milk, taking care not to overheat. Cook another 5 minutes until thickened and reduced, stirring often. The consistency should be a loose gravy. Taste, adding more salt/pepper as needed.
8. Stir in 3/4 cup of the cheddar cheese, then pour the mixture into the prepared baking pan. Sprinkle with the remaining 1/4 cup cheddar cheese.
9. Starting at the edge, closely layer the potato slices around the pan, working inward, then dot with more butter.
10. Place in the oven and bake for 40-45 minutes until the mixture is bubbling and the potatoes are golden brown and crisp. Remove from the oven and let stand for 15 minutes, then sprinkle with fresh parsley and serve.