In a bowl, mix together the chickpea flour, nutritional yeast, turmeric, black salt, and black pepper.
Add the water and use a small whisk or fork to combine.
Add the spinach with an extra splash of water (about 1tbs) and stir to combine. The mixture thickens as it sits, so if it has thickened a lot before adding to the skillet, just add another splash of water.
In a small non-stick skillet, heat about 1tbs of oil on medium heat. Once it is hot, pour the egg mixture in the pan and spread evenly (this will be more necessary if you added spinach). Cover the pan for 1-2 minutes, then remove the lid and add the cheese to one side of the omelette. Once the sides of the omelette start to lift easily, slide a spatula under the other side of the omelette and fold over the cheese. Allow to cook for another 2 minutes until the cheese is melted through. Enjoy while hot!