Cheesy Potatoes Au Gratin

Cheesy Potatoes au Gratin - thinly sliced potatoes layered and baked in a creamy, cheesy sauce with a jolt from nutmeg and thyme. The ultimate potato side dish of all time that goes well with just about anything. Utterly delicious and super comforting!

Course Side Dish
Cuisine French
Keyword au gratin potatoes recipe, potatoes au gratin
Prep Time 20 minutes
Cook Time 45 minutes
Servings 8 - 10
Calories 293.14 kcal
Author Imma


  • 2 ½- 3 pounds (1.1 - 1.3 kilos) potatoes , peeled and thinly sliced (about 7 cups)
  • 3 tablespoons (42 g) butter
  • ½ cup (57.5 g) chopped onion
  • 2 tablespoons (16 g) minced garlic
  • 2 teaspoons (2 g) fresh thyme
  • 3 tablespoons (30 g) all-purpose flour
  • ½ cup (120 g) heavy cream (sub with milk)
  • 1 ½ cup (120 g) whole milk
  • 5 ounce (141 g) evaporated milk
  • 1 ½ teaspoons (7.5 g) salt or more , adjust to taste
  • pepper to taste
  • ¼ teaspoon (0.50 g) grated or ground nutmeg
  • ¾ cup (84.75 g) shredded Cheddar cheese
  • ¾ cup (84.75 g) Gruyere , (sub with extra cheddar cheese or Jarlsberg)
  • Sprig of thyme for garnish , (optional)


  1. Preheat oven to 400℉.

  2. Peel and wash potatoes, then slice into about 1/8' thin slices. Use a mandolin, if desired, for even and fast prep.

  3. Melt the butter in a large saucepan over medium heat. Add onions, garlic and thyme. Saute for about 1 -2 minutes or until fragrant. Be careful not to let the garlic burn.

  4. Whisk in flour until fully combined.

  5. Gently pour in cream, whole milk, and evaporated milk, followed by salt, pepper, and nutmeg. Bring the cream mixture to a boil and simmer over medium heat, stirring occasionally for about 5 minutes, or until mixture starts to thicken.

  6. Add about ½ cup of shredded cheddar cheese and ½ cup of Gruyere cheese or Jarlsberg or another cheddar cheese and stir until smooth. Remove saucepan from heat.

  7. Grease a 9x13 casserole dish with butter or cooking spray.

  8. Place half of the potatoes in the greased pan, top potatoes with the sauce, add the rest of the potatoes and any other remaining sauce .

  9. Cover the dish with foil paper and bake for about 45 -50 minutes or until potatoes are fork tender . Take foil off of dish and sprinkle remaining cheese over top and bake for another 15- 20 minutes or until potatoes are bubbly and brown. Optional: Broil for 5 minutes more for a crustier and browner top.

  10. Top with thyme sprig, if desired. Serve warm.

Recipe Notes

  1. Russet potatoes or Yukon make the best potato choices for this recipe.
  2. To make ahead, simply prepare and assemble the dish up until the baking part, then cover it with tinfoil and into the fridge overnight.
  3. Please keep in mind that nutritional information is a rough estimate and can vary greatly based on products used.