1. Preheat oven at 350 degrees, or put it in at whatever your oven temp is at while you are roasting your meat or poultry. This dish is very flexible, but adjust time according to your oven temp, at lower temperature it will obviously need a little more time. And it is like making lasagna, you will simply be making layers with the ingredients.
2. O.k. starting with that casserole dish, butter it up but good including the sides.
3. Next starting with those sliced potatoes, place in a circle creating a layer of potatoes. Make sure you leave the nice perfect slices for the top layer.
4. Combine all other ingredients in separate bowl except for liquid to make layering process easier. Mix till flour and cheese are well incorporated.
5. Sprinkle this mixture over your first layer of potatoes.
6. Guess what? Start all over with a new layer of potatoes and repeat process of sprinkling remaining ingredients except for milk.
7. Once you have completed all your layering, you now know how to layer bricks for your next home improvement project - ok just kidding here folks, just making sure you are paying attention. Back to business...
8. Next add enough of your chosen liquid to just cover the potatoes.
9. Cover with lid or tin foil and shove the darn dish into that oven of yours. You can prepare this dish up to 3 hours ahead and leave it in fridge till ready to bake.
10. At last half hour, remove lid/tinfoil. If potatoes are not looking brown enough for you, you can certainly turn up the oven, but pay attention to avoid burning cheese topping. Let stand a bit before serving - perfect while the roast is resting as well.
11. And call your peeps to the dinner table to enjoy!