Step 1

Preparation Place dill bunch in a food processor and finely grate grapefruit and lemon zest directly into bowl; save fruit for another use. Add salt, brown sugar, and peppercorns and process until combined (you can also chop the dill by hand and mix it with the other ingredients in a medium bowl).

Step 2

Place a large sheet of parchment paper on a large rimmed baking sheet and pour one-third of cure lengthwise down the center of parchment. Lay salmon skin side down on top of cure and pack remaining cure in an even layer onto flesh side. Fold parchment up and over fish and cover with another sheet of parchment paper. Wrap tightly with plastic. Place another large rimmed baking sheet on top of fish and set a heavy pot or cast-iron skillet in baking sheet to weigh down. Chill 3 days.

Step 3

Unpack fish and wipe off cure with a damp kitchen towel (do not rinse). Slice very thinly with a long sharp knife, wiping down blade occasionally with another kitchen towel to keep it clean. Arrange salmon on a platter; serve with bagels, bialys, bread, cream cheese, red onion, capers, dill sprigs, and/or lemon wedges if desired.

Step 4

Do Ahead Wrap leftover salmon and refrigerate for up to 3 days.