In a small skillet, toast the caraway seeds over moderate heat, shaking the pan, until fragrant, about 1 minute. Transfer to a mortar. Add the salt and, using a pestle, coarsely crush the seeds and salt. Transfer to a small bowl.
In the skillet, toast the black and white sesame seeds over moderate heat, shaking the pan, until fragrant and the white seeds are golden, about 2 minutes. Transfer to the small bowl and stir in the granulated garlic and onion.
In a large saucepan, combine the oil and popping corn. Cover and cook over moderately high heat until the corn starts to pop. Continue cooking, shaking the pan occasionally, until the corn stops popping, 3 to 5 minutes. Transfer to a large bowl, add the melted butter and toss to coat. Add the everything-bagel spices and toss again. Serve.
Recipe by Allons-Eat! at https://www.allonseat.com/everything-bagel-popcorn/