Ingredients:

  • 1 Tbsp Unsalted Butter
  • 3 medium Russet or Yukon Gold Potatoes (about 14 oz), diced into 1/2-inch cubes
  • 1/4 cup finely diced Yellow Onion or Shallot
  • 1 cup diced Pre-cooked Ham
  • 1/2 tsp Kosher Salt, plus more for seasoning
  • 1/4 tsp Black Pepper, freshly ground
  • 4 Large Eggs
  • 1/2 cup Whole Milk or Half-and-Half
  • 1 tsp Dijon Mustard
  • Pinch Ground Nutmeg
  • 1 cup shredded Sharp Cheddar Cheese, divided
  • 1 Tbsp Fresh Chives or Parsley, finely chopped

Instructions:

  1. Preheat the oven to 375°F (190°C). Lightly grease an 8x8 inch baking dish.
  2. Melt the butter in a large skillet over medium-high heat. Add the diced potatoes and sauté, stirring occasionally, for 8-10 minutes until they are tender-crisp and lightly golden on the edges. Season lightly with salt and pepper.
  3. Reduce heat to medium. Add the diced onion/shallot and cook for 2 minutes until softened.
  4. Add the diced ham to the skillet and cook for 1 minute just to warm through. Remove the potato-ham mixture from the heat and set aside to cool slightly.
  5. In a medium bowl, whisk together the eggs, milk (or half-and-half), Dijon mustard, nutmeg, 1/2 tsp salt, and 1/4 tsp pepper until completely combined and slightly frothy.
  6. Transfer the potato and ham mixture to the prepared baking dish. Scatter 3/4 cup of the shredded cheddar cheese over the solids. Toss gently to distribute evenly.
  7. Slowly pour the egg custard mixture evenly over the potato and ham mixture. Press down gently with a fork to ensure the potatoes are completely submerged and the custard is well distributed.
  8. Allow the assembled casserole to sit for 5-10 minutes before baking so the liquid fully absorbs into the ingredients.
  9. Cover the dish loosely with foil and bake for 25 minutes.
  10. Remove the foil. Sprinkle the remaining 1/4 cup of cheddar over the top. Bake uncovered for another 10-15 minutes, or until the top is golden brown and the center is set (internal temperature should reach 165°F/74°C).
  11. Remove the casserole from the oven and allow it to rest on a wire rack for 10 minutes before slicing. This is crucial for a clean slice.
  12. Sprinkle with fresh chives or parsley before serving.