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potatoes au gratin

My Mom's Au Gratin Potatoes

My mom didn't follow a recipe, but adjusted ingredients depending on the number of servings needed, usually a crowd. I've adapted the recipe to fit in a 9 or 10 inch square baking dish (about 1 .5 quart capacity). It makes 8 small servings, plenty to serve 4 with some leftovers. My favorite cheese for this recipe is Gruyere. Other good options include sharp Cheddar, Monterey Jack, or any good melting cheese.
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Author Margie
Prep Time 25 minutes
Total Time 1 hour 45 minutes
Servings 8 (1/2 cup) portions

EQUIPMENT

  • 9 - 10 inch square baking dish (1.5 quart capacity)

Ingredients
  

  • 2 pounds Russet baking potatoes about 6 medium
  • 1 ½ cup half and half
  • ¼ cup all-purpose flour
  • ½ teaspoon onion powder
  • ½ teaspoon garlic powder
  • ½ teaspoon dry mustard
  • 3 Tablespoons unsalted butter, divided
  • 4 oz Gruyere, shredded, divided, or other cheese (about 1.5 cups loosely packed shreds)
  • 1 teaspoon salt, divided
  • black pepper, to taste
  • ¼ teaspoon paprika

Instructions
 

  • Preheat oven to 400 degrees F. Use a bit of the butter to grease the baking dish (9 or 10 inch square or 1.5 quart capacity). Cut remaining butter into small cubes. Shred the cheese.
  • Combine the half and half, flour, onion powder, garlic powder, and dry mustard in bowl large enough to accommodate all the potatoes. Whisk until the dry ingredients are thoroughly combined with the half and half.
  • Peel the potatoes. Slice into 1/8-inch (about 3 mm) rounds. (If you use a mandoline, use the safety hand guard.) Transfer potato slices to the bowl with half and half mixture. Stir to coat all the potato slices.
  • At this point, it helps to eyeball the potatoes and estimate what one third of the total would be. If you like, divide the cheese, butter, and salt into three even portions (or use the eyeball method going forward).
  • Layer a third of the potatoes in the bottom of the baking dish. (Remove potato slices from bowl with half and half and transfer to the baking dish). Overlap the potatoes to cover the entire bottom of the dish. Sprinkle a third of the salt (roughly heaping 1/4 teaspoon) and a third of the cheese (about 1/2 cup) evenly over the potatoes. Scatter a third of the butter cubes on top. Sprinkle on black pepper to taste.
  • Repeat for second layer. Place a third of the potatoes in the baking dish over the first layer. Sprinkle a third of salt (roughly heaping ¼ teaspoon) and third of cheese (about 1/2 cup) over the potatoes. Scatter a third of the butter cubes on top. Sprinkle on black pepper to taste.
  • Repeat for third and final layer. Place the final third of potatoes, salt, and cheese in the baking dish. Scatter the final third of butter cubes on top. Sprinkle black pepper on top if desired.
  • Pour the remaining half and half mixture over potatoes in the baking dish. Sprinkle paprika evenly over the top.
  • Cover baking dish with oven-safe lid or foil. (Allow space between foil and cheese, or oil the underside of the foil.) Place in oven and bake covered for 60 minutes or until the potatoes are mostly but not all the way tender at the center (slight resistance). The half and half will be mostly absorbed and there will be some bubbling oil around the edges.
  • Remove lid (or foil) from baking dish and bake uncovered for another 20 minutes or until potatoes are tender and the top is lightly golden brown.
  • Allow to cool for 10 minutes before serving.

Notes

  1. Slice the potatoes into uniformly wide (3 mm) rounds. You can do this by hand with a chefs knife. If you use a mandoline, I strongly recommend that you use the protective hand guard to avoid injury. 
  2. Putting the sliced potatoes into the half and half mixture serves two purposes. It prevents the potatoes from discoloring and also helps to promote even coverage with the half and half mixture. 
  3. I've experienced variable cooking times over the years in different ovens. Adjustments to cooking time may be required. I recommend checking the potatoes after about 50 minutes. If they are tender or mostly tender at the center and the liquid has been absorbed (no half and half visibly bubbling around the edges, just oil), you can remove the lid and continue cooking uncovered till potatoes are tender and top is golden brown. On the other hand, if the potatoes still seem quite firm, you may need to extend the covered cook time beyond 60 minutes.