Heat the oven to 150C / 300F. Line a 13 x 18-inch / 33 x 46 cm sheet pan with parchment paper.
Crack the egg white into a mixing bowl and whisk until frothy and slightly foamy, about 30 seconds.
Add the almonds and olive oil to the bowl. Toss with a spoon until every almond is coated in a thin, even layer.
Sprinkle the everything bagel seasoning and kosher salt over the almonds. Toss again until the seasoning clings evenly to each nut.
Spread the almonds in a single layer on the prepared sheet pan. Give them space, crowding traps steam and keeps the coating from crisping.
Roast for 18 to 20 minutes, stirring once at the 10 minute mark, until the almonds smell toasted and the seasoning looks golden.
Pull the pan from the oven and let the almonds cool completely on the pan, at least 10 minutes. They crisp up as they cool, so don't judge the texture while they're hot.
Break up any clusters once cooled, then transfer to an airtight jar for storage.