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Slow Cooker Potato, Leek, and Kale Gratin With Too Much Cheese

This recipe crafts a decadent slow-cooked gratin featuring thinly sliced potatoes, tender leeks, and nutrient-rich kale. Bathed in a rich cream and stock mixture, it's generously layered with a trio of Gruyère, Parmesan, and creamy blue cheese, creating an intensely flavorful and comforting dish. Ideal for a hearty main course, it promises a meld of savory, cheesy goodness with minimal hands-on effort.
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Servings: 6 people
Course: lunch/dinner
Cuisine: French
Calories: 3675.4
Ingredients Equipment Method Notes

Ingredients
  

Main
  • 1 tablespoon olive oil
  • 2 large leeks white and light green parts only, washed thoroughly, finely sliced
  • ½ small bunch of flat-leaf kale stems removed, leaves chopped
  • 375 ml 12½ fl oz; 1½ cups heavy cream
  • 125 ml 4 fl oz; ½ cup chicken or vegetable stock
  • 85 g 3 oz gruyère, grated
  • 125 g 4½ oz Parmesan, grated
  • 150 g 5½ oz creamy blue cheese
  • 900 g 2 lb washed potatoes (I use sebago), sliced about 3 mm (¼ in) thick

Equipment

  • 1 Slow Cooker
  • 1 Large Skillet
  • 1 Mandoline or Sharp Knife For uniform potato slices
  • 1 Large Bowl For mixing cream and cheese
  • 1 Whisk

Method
 

  1. Prepare leeks and kale: Wash and thinly slice leeks (white and light green parts), and chop kale leaves after removing stems.
  2. Slice potatoes uniformly: Wash potatoes and slice them about 3mm (1/4 inch) thick, ideally using a mandoline for consistency.
  3. Sauté leeks: In a large skillet, heat olive oil over medium heat. Add sliced leeks and cook until softened and translucent, about 5-7 minutes.
  4. Combine liquids and cheeses: In a large bowl, whisk together heavy cream and chicken or vegetable stock. Stir in the grated Gruyère and Parmesan cheeses.
  5. Layer the gratin: Lightly grease the slow cooker insert. Begin layering with a third of the sliced potatoes, followed by half of the sautéed leeks, half of the chopped kale, and half of the creamy blue cheese.
  6. Continue layering: Pour a third of the cream mixture over the layers. Repeat the potato, leek, kale, and blue cheese layers once more.
  7. Final layers: Top with the remaining potatoes, ensuring they are evenly distributed. Pour the remaining cream mixture over everything, making sure the potatoes are largely submerged.
  8. Slow cook: Cover the slow cooker and cook on low for 4-6 hours, or until the potatoes are completely tender when pierced with a fork.
  9. Optional finish: For a golden-brown crust, transfer the gratin to an oven-safe dish and broil for 5-10 minutes, watching carefully to prevent burning.
  10. Rest and serve: Let the gratin rest for 10-15 minutes before serving to allow it to set and thicken slightly.

Notes

For best results, ensure your potatoes are sliced uniformly thin (3mm is perfect) using a mandoline; this guarantees even cooking. Thoroughly clean leeks to remove all grit, as they trap soil easily. When building the gratin layers, press down gently to ensure the potatoes are submerged in the creamy liquid, promoting tenderness. The specified 'too much cheese' contributes significant richness; for a slightly lighter profile, you could reduce the blue cheese or opt for a milder variety. If you desire a golden, crispy top, transfer the cooked gratin to an oven-safe dish and broil for a few minutes before serving. A touch of nutmeg in the cream mixture can elevate the flavor profile.