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Potatoes au gratin - overthinking classics

Potatoes au Gratin

This rendition of Potatoes au Gratin features thin slices of potato cooked until tender in a rich bechamel and topped with a golden lid of melted Gruyere cheese and crisp breadcrumbs.
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Prep Time 30 minutes
Cook Time 1 hour 20 minutes
Course Side Dish
Servings 8

Equipment

  • 1 10" gratin dish
  • 1 skillet
  • 1 small saucepan
  • 1 mandoline
  • 1 Food Processor

Ingredients
  

  • 2 cups 2% milk
  • 4 shallots quartered
  • 2 cloves garlic smashed
  • 1 tbsp fresh thyme leaves **
  • ½ cup panko breadcrumbs
  • 2 tbsp unsalted butter
  • 2 tbsp all-purpose flour
  • 1 tbsp Dijon mustard
  • 1 tsp salt
  • ½ cup heavy cream
  • 2-3 Russet potatoes *** sliced thin on a mandoline
  • 150g (5oz) gruyere shredded
  • fresh sage leaves to garnish

Instructions
 

  • Pour the milk into a small saucepan. Add the shallots, garlic, and fresh thyme leaves. Bring the milk to the verge of boiling, then reduce the heat to a simmer. Simmer the milk for 15 minutes or until the shallots are tender. 
    2 cups 2% milk, 4 shallots, 2 cloves garlic, 1 tbsp fresh thyme leaves **
  • While the milk is simmering, preheat the oven to 325°F. Grease a casserole or gratin dish with butter and set it aside.
  • Pour the breadcrumbs into a dry skillet and place over medium heat. Toast until golden, shaking the pan frequently. Transfer the breadcrumbs to a bowl and set them aside.
    ½ cup panko breadcrumbs
  • When the milk is done simmering, take it off of the heat and transfer it to a food processor. Blitz the mixture until smooth. Pour the mixture into a large measuring cup and set it aside.
  • Place the butter in a small saucepan over medium heat. When the butter melts add the all-purpose flour and whisk the two together to form a roux. Slowly whisk the milk mixture into the roux, making sure each addition is fully integrated before adding more. 
    2 tbsp unsalted butter, 2 tbsp all-purpose flour
  • Once all the milk is in, add the mustard and salt. Stir to combine. Take the sauce off of the heat and whisk in 1/2 a cup of cream.
    1 tbsp Dijon mustard, 1 tsp salt, ½ cup heavy cream
  • Arrange the slices in the dish you prepared earlier. Fan the potatoes out until they cover the bottom of the dish. Sprinkle them with salt and pour a third of the sauce on top. Add a little of the gruyere but be sure to reserve 100g for the top. Repeat until you have three layers of potatoes finishing with the final third of the sauce. Don't put cheese on top of the final layer of sauce.
    2-3 Russet potatoes ***, 150g (5oz) gruyere
  • Cover the potatoes with tin foil and transfer them to the oven. Bake for 65-75 minutes or until the potatoes are fork tender.
  • When the potatoes are done, take them out of the oven and turn on the broiler. Remove the foil and sprinkle the surface with the cheese, followed by the panko breadcrumbs. Return the potatoes to the oven and broil until the cheese bubbles. Keep a close watch on the gratin and rotate the dish to ensure it browns evenly.
    150g (5oz) gruyere
  • Take the potatoes au gratin out of the oven and let cool for 10 minutes. Garnish with fresh sage leaves and some fresh ground pepper and serve immediately.
    fresh sage leaves

Notes

** If you don't have fresh feel free to use dried thyme. 
*** Slice your potatoes “no thicker than a penny”. Or at least that’s what English food writer Elizabeth David advises and who am I to argue?
Keyword breadcrumbs, gruyere, potatoes