Put the onion, fennel seeds, granulated garlic, and granulated onion in a large dry saucepan over medium heat and cook for 3 minutes, stirring constantly to prevent burning. Stir in the corn, mustard, and lemon juice and cook for 30 seconds. Stir in the brussels sprouts and broth. Decrease the heat to low, cover, and cook, stirring occasionally, for 15 minutes. Stir in the thyme and cook uncovered for 1 minute longer.