Place the poppy seeds, sesame seeds, onion and garlic flakes in a dry medium skillet. Cook over medium heat, tossing or stirring often to avoid burning, until fragrant and browned. Set the everything bagel seasoning aside.
Whisk the egg white powder with the water in a large bowl. Whisk in the salt to combine.
Add the peanuts and everything bagel seasoning to the bowl and fold to combine. Transfer to a large roasting pan or rimmed baking sheet and bake until the peanuts are dry, 30 to 40 minutes.