I am making chicken with French flavors and ratatouille for Sunday’s dinner. While wife Jan and daughter Miriam love ratatouille , I am not overly fond of overcooked vegetables. I wanted a potato dish for me, cheesy potatoes—potatoes au gratin—seemed the ticket. I decided to add a bit of a twist on a standby dish and include rosemary.
Karl’s Rosemary Potatoes au Gratin
4+ Tbs. butter, separate uses
3 Tbs. AP flour
1 tsp. dried rosemary, ground
½ tsp. black pepper, cracked
½ lb. sharp cheddar cheese, grated
3 lb. yellow potatoes, sliced thinly
(optional) 1 small yellow onion, sliced thinly
1. Put three tablespoon of butter into a medium pot over a medium heat.
2. Stir the three tablespoon flour into the melted butter.
3. Cook, stirring frequently, until it forms a blond roux.
4. Whisk in the milk, rosemary and pepper.
Tip: While I used dried rosemary, feel free to use fresh.
5. Continue cooking until there are no lumps and the sauce starts to thicken.
6. Whisk in the shredded cheese, until it is completely melted and combined into the sauce.
Tip: Keep the sauce warm over the lowest heat, while you prepare your casserole.
Note: You will be serving this dish directly from your casserole. You will want to use an attractive, table-ready casserole.
7. Use the last tablespoon of butter to grease your casserole well.
Tip: You want the sides as well as the bottom well coated with butter.
8. Slice the potatoes into ⅛ inch thick slices.
Tip: A mandoline is a very useful tool for making even slices.
9. Arrange your potatoes in a shingled spiral over the bottom of the casserole.
Tip: Start this process with your smallest and ugliest slices. Save the largest and prettiest for the top layer that will be exposed.
10. When the bottom of the casserole is completely covered, carefully spread one third of the cheese sauce over the potatoes.
Tip: If using onion shingle the slices of onion over the sauce.
Note: Calculate how many layers of potatoes that your casserole will hold and adjust your sauce accordingly—my casserole held three layers. If your casserole will hole only two layers divide the sauce in half. If it will hold four layers divide your sauce into quarters.
11. Lay out the second layer of potatoes and cover them with one third of the sauce.
12. Using the best slices, arrange the top layer of potatoes in an attractive spiral and cover with the last of the cheese sauce.
Tip: If using onion, dice any remaining onion and sprinkle it on top of the sauce.
13. Cover the casserole and place it on the middle rack in 350 F oven.
Tip: Place an empty baking sheet on the rack under your casserole to catch any cheesy drips.
Note: If your casserole does not have a lid use a sheet of aluminum foil to seal it tightly.
14. Bake the potatoes for one hour.
Tip: This dish can be made up to this point the day before, so that if you are planning a large meal you can refrigerate it over night and pop it into the oven just before serving.
15. Remove the lid/foil and switch the oven heating element to broil.
16. Broil the casserole until the cheese is spotty and browned.
Tip: If you have let the casserole go cold, bake the dish for 20 minutes at 350º F, before broiling.
17. Remove the casserole from the oven and let it cool for ten minutes.
Tip: The potatoes au gratin will be scalding hot right from the oven. You want to serve it warm, not dangerously hot.
18. Serve directly from the casserole.