Sichuan Spice Salmon Gravlax

45 grams salt 1/3 cup Diamond Crystal kosher salt OR 1/4 cup Morton kosher salt OR 2½ tablespoons table salt
1 tablespoon whole Sichuan peppercorns 4 grams
2 teaspoons fennel seeds 4 grams
900 grams skin-on Atlantic salmon or quality wild salmon fillet 2 lbs
25 grams dark brown sugar 2 packed tablespoons

Combine the salt, Sichuan peppercorns, and fennel seeds in a skillet or wok. Set over medium heat and toast, stirring frequently, until the spices are fragrant, about 5 minutes. Optionally, pound the spices into the salt in a mortar and pestle.
In a medium bowl, stir together the spiced salt and brown sugar until evenly distributed. Line a tray with plastic wrap, leaving a generous amount of overhang to wrap the entire salmon fillet later. Spread half of the salt mixture in the center of the plastic wrap. Pat the salmon fillet dry with paper towels and lay it on top of the salt mixture. Top with the remaining salt mixture. Wrap the fillet tightly with plastic wrap and weigh it down with a heavy object on top (I like to use a baking dish).
Cure in the refrigerator for 48 hours, up to 72 hours if you prefer a saltier cure. Flip the salmon fillet over once a day, keeping it well covered and replacing the weight on top. It's normal for the salmon to release a small amount of liquid into the tray as the salt and sugar draw out moisture.
To serve, scrape off the excess cure on the surface and rinse in cool water. Pat the surface dry with a paper towel then thinly slice on a bias using a gentle sawing motion without cutting through the skin.
Serve open faced on buttered toast with mustard sauce, on bagels with cream cheese, or on crackers with creme fraiche. Refrigerate leftovers tightly wrapped in plastic in an airtight container for up to 3 days.

To scale up the recipe, use 5% the total weight of the salmon in salt, 3% in sugar, and 1-2% in spices.

Riff on this recipe by swapping the spices for your favorites or by adding chopped herbs like dill and citrus zest.