Step 1

Using a microplane zester or a box grater on the finest setting, grate approximately one half of your salt-cured egg yolk. You should have about 1 heaping tablespoon of grated yolk.

Step 2

Place popcorn kernels and oil in a large saucepan and swirl until all the kernels are coated. Place a lid over the mixture and set to medium high heat, cooking until most of the kernels have stopped popping. This should take between 4-10 minutes.

Step 3

While the popcorn is popping, melt the butter in the microwave or on the stove top. Place 1 teaspoon of sugar and the grated egg yolk into your mortar and pestle. Combine until the sugar is incorporated and you have a paste, not chunks. Add the remaining teaspoon of sugar into the hot butter and stir until dissolved. Add the egg yolk paste to the sugar and butter mixture, and stir to combine. The mixture should form a loose sauce.

Step 4

When most of the popcorn kernels have finished popping, remove from heat and immediately pour the popcorn into a large, wide bowl. Drizzle the sauce over the kernels evenly and mix with a wooden spoon to distribute. Sprinkle the optional sumac over the kernels and serve immediately.