Ingredients

• 1 3/4 cups kosher salt
• 1 1/4 cups sugar
• 4 large egg yolks
• Nonstick vegetable oil spray

Instructions

1. Whisk 1 3/4 cups kosher salt and 1 1/4 cups sugar in a medium bowl to combine. Evenly spread out half of salt mixture in an 8x8" glass baking dish. Using the back of a tablespoon, create 4 depressions in salt mixture, spacing evenly. Carefully place a large egg yolk (4 total) in each depression. Gently sprinkle remaining salt mixture over yolks and tightly wrap dish with plastic. Chill 4 days.
2. Preheat oven to 150°F. Brush salt mixture off each yolk, then carefully rinse under cold water to remove any remaining salt (yolks will be semi-firm, bright, and translucent). Gently pat dry with paper towels.
3. Generously coat a wire rack set inside a rimmed baking sheet with nonstick vegetable oil spray; place yolks on rack. Dry out in oven until opaque and texture is like a firm Gruyère cheese, 1 1/2–2 hours. Let cool. (Alternatively, if your oven doesn't go that low, you can dry out eggs in an unheated oven for 2 days.)
4. Yolks can be cured 1 month ahead. Place in an airtight container and chill.