Make the batter: In a bowl, whisk together chickpea flour, turmeric, black salt, nutritional yeast, and water until smooth.
Sauté the veggies: Heat 1 tbsp olive oil in a pan. Add onion, bell peppers, mushrooms, and spinach. Cook for 4–5 minutes. Season with salt and pepper. Set aside.
Cook the omelettes: Heat a non-stick pan over medium heat. Add a little oil. Pour ¼ of the batter and spread into a circle.
Add the filling: Once bubbles form and edges lift (about 2–3 minutes), spoon some veggies on one half. Fold the omelette over.
Finish cooking: Let it cook 1 more minute, then remove. Repeat for remaining batter.
Serve hot with toast, avocado, or salad.