Preheat the oven to 400 degrees F and grease your muffin tray with the coconut oil.
Heat the oil in a large skillet over medium heat, and add the chopped onion, bell pepper and mushrooms. Cook for 5-7 minutes, until reduced. Remove from heat and add the green onion and mix into the veggies.
Meanwhile, in a large bowl, add the chickpea flour, nutritional yeast, seasonings and baking powder and whisk to combine. Then pour in the water and mix well.
Evenly divide the veggie mixture between your 12 muffin cups, about 1 heaping tablespoon per muffin. Then add the chickpea mixture over top each one, filling to the top. (I used my 1/4 measuring cup to divide the mixture.) Then, using a spoon, stir each muffin gently, to ensure the chickpea mixture reaches the bottom of each muffin cup.
Bake for 30 minutes and remove from the oven. Let cool for 5-10 minutes before gently removing from the tray and serve warm, or at room temperature.
Do not use paper muffin cups in place of greasing your muffin tray. The mixture will get stuck to the paper cup and you will lose a lot it this way.