Cut the veggies: Thinly slice the scallions and save the dark green parts for later. Core the bell peppers, cut them into slices, and in small dice.
Roast the veggies: Place white and light green scallions and the peppers on a parchment-lined sheet pan (9.5" x 13" or 25 x 33cm) or in a large baking dish. Roast them for 10 minutes in the oven.
Make "egg" mixture: Add the silken tofu, water, chickpea flour, nutritional yeast, salt, and turmeric to a blender (or a high-rise container if using an immersion blender). Blend until smooth.
Bake: Remove the sheet from the oven. Pour the silken tofu mixture on top of the veggies and spread it out with a spatula. Top with the dark green parts of the scallions. Bake for 20 minutes.
Slice: Cut the sheet pan "eggs" into squares with a pizza roller.