(With recommendations and recipes)
We wanted to know everything we could about making scalloped, and au gratin potato casseroles. We read what we could in our textbooks and began studying recipes. Then we stopped by our local potato warehouse for a 50-pound box of Russet potatoes. (Yes, in Eastern Idaho, we have potato warehouses scattered about like convenience stores. Most will sell to consumers. We paid $12 for a box of premium, extra-large bakers.)
As we reviewed our recipes, we found that many of them called for partially cooking the potato slices before baking. We used that as a starting point. We made several casseroles by boiling the potato slices until they were crisp tender and assembling them in baking dishes. We were disappointed. The casseroles turned out with over-cooked, mushy potatoes. They tasted bland and the casseroles were watery. We concluded that the boiling bleached out much of the potato flavor and absorbed tons of water that diluted the casseroles. We found that if we sliced the potatoes thinly–about 1/8-inch or a little thicker–they would cook evenly without par-cooking.
It’s important that you slice the potatoes uniformly. If you don’t, your casserole won’t cook evenly: the thin slices will be mushy while the thick slices are still hard. The only way to cut the slices evenly is with a mechanical slicer. Our slicer of choice is a mandoline.
As we continued to course through the recipes in our cook books and text books, we found that potato casseroles can be categorized by their structure: those that are made with eggs, those made with a white sauce and flour, and those that rely on the starch from the potatoes for structure. Now that we knew how to cook the potatoes, we started experimenting with these three types. All three were successful.
The egg based casseroles cooked into a firm casserole but moist. From that casserole, we could cut neat, formal-looking wedges or squares. This would be our choice for a formal party.
Both the white sauce and cream based casseroles worked well too. We expected the cream based ones to be overly runny but they weren’t. So all three worked. The advantage to the white sauce type is that you don’t need to be as careful in the cooking; the white sauce is less likely to curdle than cooked milk or cream.
You can use any of these recipes types. We have given you optional ingredients to add like ham or onions or garlic. We recommend:
- Using a mandoline or other cutting device to assure that the slices are of uniform thickness.
- Cutting the slices not thicker than 3/16 inch.
- Do not boil your potatoes before making the casserole.
See the recipes: