Vegan Chickpea Frittata

Name: Vegan Chickpea Frittata
Ingredients: 1 cup chickpea flour; 2 tablespoons nutritional yeast; 1 teaspoon baking powder; ½ teaspoon kala namak (black salt) or regular salt (see Tip); ¼ teaspoon ground turmeric; ¼ teaspoon ground pepper; 1 cup water; 2 tablespoons lemon juice; 1 teaspoon reduced-sodium tamari or soy sauce (see Tip); 3 teaspoons extra-virgin olive oil, divided; 1 cup thinly sliced red onion; 1 cup sliced cremini mushrooms; 2 teaspoons finely chopped garlic; 1 cup grape tomatoes, halved lengthwise; 1 cup packed fresh spinach, roughly chopped