Best Potatoes Dauphinoise Recipe (Potatoes au Gratin)
Potatoes Dauphinoise or potatoes au gratin is a classic French side dish. Potatoes layered with herb-infused cream and Gruyère cheese, baked to golden, bubbly perfection! Naturally gluten-free!
Grease a 9x13x2 inch casserole dish (glass or ceramic preferred) with 1 tablespoon butter, set aside. I smoosh the butter in the dish using a paper towel to schmear evenly.
Bring milk, cream, garlic, rosemary, thyme, salt and pepper to a low simmer. Cooking on low for 30 minutes. Strain out herbs and garlic into a bowl, discarding the herbs and garlic. Reserve infused cream mixture.
While your cream mixture simmers, slice the potatoes ⅛ inch thick -- if you've never used a mandolin slicer give it a try, your slices will be even and uniform and be done lickity-split! Place sliced potatoes in a bowl of cold water until ready to assemble, then drain and pat dry.
Assembling & Baking Potato Gratin
Arrange potatoes in rows, overlapping slightly; seasoning each layer with sea salt and pepper. Sprinkle a handful of Gruyere cheese over potatoes and pour ½ cup cream mixture over the potatoes. Repeat steps twice, finish by pouring on an remaining cream mixture. Dot with 1 tablespoon butter; cover with foil and bake.
Bake in preheated 375°F /(190° C) oven for 45 minutes; then remove foil and continue baking, uncovered for an additional 45 minutes, until golden brown and bubbly and potatoes are fork tender (insert fork into potatoes; they should yield to gentle pressure).
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Notes
Tips for Making Ahead
Bake gratin for a total of about 60 minutes undercooking potatoes slightly, remove from oven and cool quickly by placing in refrigerator (be careful and place a hot pad or trivet on your fridge shelf. Remove them when they have a light brown color instead of a deep golden brown hue.
Once cooled, cover with a sheet of wax paper pressed into the potatoes (protect against freezer burn), then cover with foil and seal baking dish well.
If serving within 24-48 hours, refrigerate until ready to reheat. Or freeze up to 2 weeks for best texture and flavor, thaw in refrigerator overnight or bake from frozen (might require a bit more time).
Place in preheated 375°F oven (remove wax paper), covered for about 30-40 minutes, removing foil last 10 minutes to brown. It should be bubbly around the edges and warmed in the center with a deep golden brown hue.
To determine if warmed through, stick a butter knife in the middle of the gratin, holding for about 30 seconds. Remove knife, if warm or hot to touch, they are warmed through, if cool to touch, return to oven in 15 minute increments, covering with foil if browning too quickly.
While you can prepare the dish and not bake, the potatoes will oxidize and turn a purple-brown color, while this will not harm you, the color isn't pretty, so instead bake and rewarm the day of serving.