I started making these egg yolks a week ago, but with the long rest in the refrigerator, these are a week-long project. Luckily most of that time is just waiting for them to do their thing. This is a great way to use up extra yolks that you have laying around, because they can definitely substitute for cheese when you need a little umami boost. And look at that beautiful color!
Salt-Cured Egg Yolks
From America's Test Kitchen as seen on The Splendid Table
1 pound kosher salt
1 pound granulated sugar
12 large eggs
Working with 1 egg at a time, crack eggs, separate yolks from whites, and transfer yolks to indentations in salt bed. Carefully pour remaining salt mixture evenly over yolks. Wrap pan with plastic wrap and refrigerate until yolks are firm and dry throughout, 6 to 7 days.
Adjust oven rack to middle position and heat oven to 200°F. Set wire rack in rimmed baking sheet. Fill medium bowl with cool water. Remove yolks from salt mixture, brushing off excess, and rinse gently in water. Pat yolks dry with paper towels and transfer to wire rack. Transfer sheet to oven and bake until exteriors of yolks are dry to touch, 30 to 40 minutes.
Grate or thinly slice yolks and sprinkle on your favorite dishes, from pasta and risotto to roasted vegetables and buttered toast. You use them almost like you would a hard cheese. They add a nice and nutty, deeply umami flavor. Cured yolks can be refrigerated in airtight container for up to 2 weeks. The yolks can also be frozen, though the time they last depends on many factors. The water activity in a properly cured and dried yolk is so low that they hardly ever spoil after months of hanging out in the fridge.