Nori Powder

To toast nori, grab 1 sheet at a time with tongs and hold about 2 inches above low flame on gas burner. Flip nori sheet every 3 to 5 seconds until nori is aromatic and shrinks slightly, about 20 seconds. Alternatively, toast nori in oven—spread nori evenly on 2 rimmed baking sheets and bake in 275-degree F/135-degree C oven until nori is aromatic and shrinks slightly, 20 to 25 minutes, flipping nori halfway through toasting. Tear nori sheets into rough 1½-inch pieces.

If using spice grinder, loosely pack grinding chamber three-quarters full with nori pieces and grind until nori turns to fine powder, about 30 seconds. Without emptying spice grinder, add more nori pieces until grinding chamber is three-quarters full; grind until nori turns to fine powder, about 30 seconds. Transfer nori powder to airtight container. Repeat grinding process twice with remaining nori pieces. If using blender, add half of nori pieces to blender jar, cover tightly with lid, and process on high speed until nori turns to fine powder, about 45 seconds. Add remaining nori pieces and continue to process on high speed until nori turns to fine powder, about 45 seconds longer. Nori powder can be stored in airtight container at room temperature for up to 2 months.