In a mixing bowl, whisk together the chickpea flour, nutritional yeast, cornstarch, salt, and black pepper until combined.
Pour the vegetable broth into the flour mixture and whisk until smooth. Allow to sit for 5 minutes to thicken slightly.
Heat a pan or well-seasoned cast-iron skillet over medium heat. Spray the pan with a thin layer of cooking oil. Once it's hot, scoop out ⅓ cup of chickpea mixture into the pan and cook on one side for 5-7 minutes or until the edges start to . brown. Flip one half over onto the other half and cook for another 2 minutes. Remove to plate and cover to keep warm or assemble sandwiches immediately. Repeat with remaining mixture.
To assemble sandwich, spread hummus on the insides of the bagel. Add a small handful of spinach, a couple slices of tomato, the chickpea vegan egg, cooked and warmed breakfast sausage, and avocado slices. Top with bagel top and enjoy!